Carl Feit | Yeshiva University (original) (raw)

Papers by Carl Feit

Springer eBooks, 1975

The basic premises underlying cancer immunotherapy are (a) that cancer cells possess cancer-speci... more The basic premises underlying cancer immunotherapy are (a) that cancer cells possess cancer-specific transplantation-like antigens, and (b) that their host is capable of mounting an immune response to these antigens that results in the rejection of the cancer cells as a homograft.

The Journal of Immunology

UK PubMed Central is a service of the UKPMC Funders Group working in partnership with the British... more UK PubMed Central is a service of the UKPMC Funders Group working in partnership with the British Library, University of Manchester and the European Bioinformatics Institute in cooperation with the National Center for Biotechnology Information at the US National ...

The Journal of Immunology

Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), bu... more Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), but not Escherichia coli-derived recombinant IFN-gamma. In addition, GIF-1 antibody failed to immunoprecipitate 125I-labeled recombinant IFN-gamma, whereas it precipitated natural IFN-gamma in a concentration-dependent manner. The lack of recognition of recombinant IFN-gamma by antibody GIF-1 may not be due to the absence of the oligosaccharide moiety in the molecules of recombinant IFN-gamma alone, because removal of carbohydrate from natural IFN-gamma by treatment with a mixture of glycosidases did not alter the selective binding of antibody, i.e., deglycosylated and untreated natural IFN-gamma were equally neutralized and immunoprecipitated by GIF-1 antibody. In addition, a minor monomeric component of natural IFN-gamma with the m.w. of 15,500, which apparently lacks carbohydrate, was also recognized by antibody GIF-1. These results suggest that the discriminative recognition of natural...

From Gene to Protein: Translation Into Biotechnology, 1982

Publisher Summary This chapter describes an ELISA assay for detecting cell surface antigens on ad... more Publisher Summary This chapter describes an ELISA assay for detecting cell surface antigens on adherent cells. The effective use of monoclonal antibodies (mAb) in the analysis of cell surface antigens is dependent upon the availability of a rapid, reproducible, quantitative assay for their detection and characterization. To meet these requirements, an ELISA assay has been developed that allows for the detection of mAb recognizing antigens on the surface of viable, anchorage-dependent cells. Its utility in identifying the potential markers of human sarcoma cells has been tested. Therefore, ELISA is a rapid, reproducible, quantitative assay for screening and characterizing mAb. This assay is useful for identifying cell surface antigens in their native unfixed state.

The Journal of Immunology

Preparations of human interferon (HuIFN) immune (gamma) (2 X 10(7) units/mg protein), HuIFN leuko... more Preparations of human interferon (HuIFN) immune (gamma) (2 X 10(7) units/mg protein), HuIFN leukocyte (alpha) (1.4 X 10(8) units/mg protein) and HuIFN fibroblasts (beta) (10(6) U/mg protein) were assessed for their influence on colony formation of human hematopoietic progenitor cells: colony forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), burst forming unit-erythroid (BFU-E), day 7 colony forming unit granulocyte-macrophage (CFU-GM) and day 14 CFU-GM. Colony formation by CFU-GEMM and BFU-E was suppressed equally by the three preparations of HuIFN, but colony formation by CFU-GM was suppressed differentially. CFU-GM were, on the whole, more responsive to HuIFN gamma than HuIFN alpha, and HuIFN beta was least effective. HuIFN alpha, but not HuIFN gamma or HuIFN beta, suppressed colony formation from CFU-GM without also suppressing the total number of colonies plus clusters. This was due to an increase in the numbers of clusters formed in the presence of HuIF...

Dr. Feit and Dr. Adams answer questions from the audience

Dr. Feit briefly explains Jewish Law and how it governs Jewish thought and action

Cancer Letters, 1993

Introduction S,, a heterophile antigen present on human sarcoma cell lines in culture, has been p... more Introduction S,, a heterophile antigen present on human sarcoma cell lines in culture, has been previously defined by this laboratory [ 1,2]. This antigen is also present in guinea-pig kidney. Purification of the antigen to homogeneity has now been achieved by a combination of ammonium sulfate fractionation, DEAE-cellulose, sephadex, high pressure liquid chromatography and affinity chromotography. S, is a monomeric protein of 70 000 Da, as indicated by the presence of a single band on SDS-PAGE. Amino acid analysis demonstrates the prevalence of glycine, lysine and glutamic acid. Aspartic acid was found to be the N-terminal residue with further sequence of glycine-valinealanine-glutamic acid (gly-val-ala-glut).

Annals of the New York Academy of Sciences, 1975

Annals of the New York Academy of Sciences, 1976

International Journal of Immunopharmacology, 1982

Carcinoembryonic antigen (CEA) is an important tumor marker, associated with many neoplasms and m... more Carcinoembryonic antigen (CEA) is an important tumor marker, associated with many neoplasms and mainly with malignancies of the human digestive tract. A~ a consequence its ~nitoring serves as a crucial means in the follow-up of cancerous state. The ability to differentiate between different types of CEA may add another dimension to this diagnostic test. We approached this issue by analysis of the specificities of different anti-CEA monoclonal antibodies. Stable clones have been established from ten hybrido~as that produced anti-CEA antibodies. These ~noclonal antibodies (McAb) were found to differ in their ability to bind individual CEA preparations: Whereas three McAb's reacted identically with four different CEA's, the other seven exhibited different reactivities. The panel of McAb's, including the three identically reactive ones, differed in their capacity to stain CEA positive human cell lines derived from various tu~mrs. This finding is at present being evaluated for its potential as a diagnostic tool. Moreover, the antibody displaying the highest degree of cross-reactivity with all tested CEA preparations has been used for one step affinity purification of CEA, from either metastatic liver or culture fluids of different established CEA-producing cell lines, for the purpose of their further characterization.

Infection and Immunity, 1974

Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast c... more Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast cells of Histoplasma capsulatum . Ribosomes from disrupted cells were isolated by differential centrifugation using sodium dodecyl sulfate. These preparations contained 55% protein and 45% ribonucleic acid and sedimented as a single peak with a sedimentation coefficient of 77 S on sucrose density gradient analysis. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intravenously with 8 × 10 6 yeast cells of H. capsulatum . Significant protection was induced by ribosomes and was greatly enhanced by adjuvants. Protection measured by 30-day survival compared favorably with the immunoprotection assessed by absence of lung lesions and negative spleen cultures. Treatment of ribosomes with ribonuclease before immunization reduced protection by 85%, whereas trypsin and Pronase reduced the protection by 50 to 55%. These findings indicate that both intact riboso...

The use of monoclonal antibodies to distinguish human sar coma from carcinoma cells has been expl... more The use of monoclonal antibodies to distinguish human sar coma from carcinoma cells has been explored. Spleen cells from a BALB/c mouse immunized with a human malignant fibrohistiocytoma were fused with cells of the mouse P3Ui plasmacytoma cell line. Antibodies were then screened for reactivity against human sarcoma and carcinoma cells growing in culture. This work has yielded 2 immunoglobulin G monoclonal antibodies VIE4 and VIF3 which, respectively, reacted with 85% (17 of 20) and 90% (18 of 20) of sarcoma lines tested but with none of eight carcinoma cell line preparations. Reactivity against normal fibroblasts was also demonstrated. By immunofluorescence, the antigens detected by the two antibodies appear to have distinc tive intracellular distributions. Immunoprecipitation with VIF3 has shown that it is detecting a protein with a molecular weight of 70,000. When tested against pathological frozen tissue sections, VIF3 reacted with four of 11 and VIE4 with three of 11 human sarc...

I would like to address myself to certain aspects of the interplay between Torah and science. Whe... more I would like to address myself to certain aspects of the interplay between Torah and science. When I deal with science, I shall be discussing biology, the branch of science with which I am most familiar; and when I deal with scientific theories, I shall be referring to the theory of evolution because of its importance and centrality in modern biology. However, I would like to emphasize that these are but models. The lessons to be learned, if any, will apply to other sciences and theories as well. Torah and contemporary science interact at many levels. I intend to define three levels of interaction and to examine what can be learned from an analysis of each of them. They are: (1) methodology; (2) substance or fact; and (3) hashkafah, or world-view.

Cancer, Sep 1, 1985

Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and re... more Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and reacting with connective tissue differentiation antigens were evaluated for their interaction with tissues obtained from patients with classic Kaposi's sarcoma. Biopsy was performed on active neoplastic lesions from the skin of 26 patients, frozen sections were prepared, and the binding of the McAbs was tested using the indirect immunofluorescence assay. Clinically uninvolved skin from the same patients as well as skin and muscle from eight non-cancer patients were treated similarly and served as controls. McAbs IXG11, 23H7, IIIE5, and 15G5 interacted strongly with the Kaposi's sarcoma lesions and weakly with the uninvolved skin in 22 of 26 (84%), 23 of 26 (88%), 12 of 14 (85%), and 1 of 6 (16%) of the patients, respectively. IXG11, 23H7, and IIIE5 interacted weakly with the skin of seven of eight non-cancer patients. McAb 15G5 was found to bind strongly to tumor lesions, to the respective uninvolved skin in four of five Kaposi's sarcoma patients, and also to skin and connective tissues of muscle from non-cancer patients. The mode of interaction was morphologically different for each McAb. It is suggested that McAbs IXG11, 23H7 and IIIE5 identify markers whose expression is markedly increased in Kaposi's sarcoma lesions as compared with uninvolved skin of the same patients. These markers may serve as immunologic probes for the investigation of this neoplastic process.

Hybridoma, 1985

Flow cytometry of cellular DNA and RNA content was employed to determine DNA ploidy, proliferatio... more Flow cytometry of cellular DNA and RNA content was employed to determine DNA ploidy, proliferation, and RNA content of hybridoma cultures shortly after cell fusion and sequentially thereafter. The parental mouse myeloma cell line P3UI was characterized by tetraploid DNA content, S-phase 50%, and high RNA, the parental mouse spleen cells by diploid DNA content, low proliferation, and low RNA content. Hybridoma cultures studied as early as 21 days after fusion were found to contain the sum of the parental cells' DNA content (hexaploid), or if less, more than that of the myeloma parental cells. Only one clone of 35 tested was shown to be hexaploid and the rest hypertetraploid or hyperpentaploid. Hybrid cell cultures were frequently found to contain a variable mixture of unfused parental cells. The high proliferation of hybridoma cells determined by flow cytometry indicates that these cells would eventually overgrow the parental cells. Flow cytometry also enabled an accurate estimat...

Cancer, Sep 1, 1985

Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and re... more Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and reacting with connective tissue differentiation antigens were evaluated for their interaction with tissues obtained from patients with classic Kaposi's sarcoma. Biopsy was performed on active neoplastic lesions from the skin of 26 patients, frozen sections were prepared, and the binding of the McAbs was tested using the indirect immunofluorescence assay. Clinically uninvolved skin from the same patients as well as skin and muscle from eight non-cancer patients were treated similarly and served as controls. McAbs IXG11, 23H7, IIIE5, and 15G5 interacted strongly with the Kaposi's sarcoma lesions and weakly with the uninvolved skin in 22 of 26 (84%), 23 of 26 (88%), 12 of 14 (85%), and 1 of 6 (16%) of the patients, respectively. IXG11, 23H7, and IIIE5 interacted weakly with the skin of seven of eight non-cancer patients. McAb 15G5 was found to bind strongly to tumor lesions, to the respective uninvolved skin in four of five Kaposi's sarcoma patients, and also to skin and connective tissues of muscle from non-cancer patients. The mode of interaction was morphologically different for each McAb. It is suggested that McAbs IXG11, 23H7 and IIIE5 identify markers whose expression is markedly increased in Kaposi's sarcoma lesions as compared with uninvolved skin of the same patients. These markers may serve as immunologic probes for the investigation of this neoplastic process.

Natural Immunity and Cell Growth Regulation, Feb 1, 1986

In an effort to determine the effect of dexamethasone on hybridoma formation, spleen cells from B... more In an effort to determine the effect of dexamethasone on hybridoma formation, spleen cells from BALB/c mice hyperimmunized with sheep red blood cells (SRBC) were fused with mouse plasmacytoma cells (P3U1) in the presence of polyethylene glycol (PEG). Dexamethasone was added in decreasing doses (10(-3) to 10(-9) mM) to the hypoxanthine-aminopterin-thymide (HAT) medium immediately after the PEG-mediated cell fusion. 10(-3) mM of this steroid was found to inhibit markedly the number and size of hybridoma clones generated, while 10(-5) mM dexamethasone was shown to enhance hybridoma formation. The effect of 10(-3) mM dexamethasone was most pronounced when added immediately after fusion. When this dose was given 48 or 120 h after cell fusion, the extent of the inhibitory effect was less pronounced. High concentration of dexamethasone may also inhibit monoclonal antibody production by hybridomas once generated. An increase in the number of clones formed was observed when 10(-5) mM dexamethasone was added to HAT medium as well as an increase in the average colony size. Large clones were also observed with lower dexamethasone doses ranging from 10(-7) to 10(-9) mM. Possible mechanisms on the effect of dexamethasone on hybridoma formation are discussed.

Springer eBooks, 1975

The basic premises underlying cancer immunotherapy are (a) that cancer cells possess cancer-speci... more The basic premises underlying cancer immunotherapy are (a) that cancer cells possess cancer-specific transplantation-like antigens, and (b) that their host is capable of mounting an immune response to these antigens that results in the rejection of the cancer cells as a homograft.

The Journal of Immunology

UK PubMed Central is a service of the UKPMC Funders Group working in partnership with the British... more UK PubMed Central is a service of the UKPMC Funders Group working in partnership with the British Library, University of Manchester and the European Bioinformatics Institute in cooperation with the National Center for Biotechnology Information at the US National ...

The Journal of Immunology

Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), bu... more Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), but not Escherichia coli-derived recombinant IFN-gamma. In addition, GIF-1 antibody failed to immunoprecipitate 125I-labeled recombinant IFN-gamma, whereas it precipitated natural IFN-gamma in a concentration-dependent manner. The lack of recognition of recombinant IFN-gamma by antibody GIF-1 may not be due to the absence of the oligosaccharide moiety in the molecules of recombinant IFN-gamma alone, because removal of carbohydrate from natural IFN-gamma by treatment with a mixture of glycosidases did not alter the selective binding of antibody, i.e., deglycosylated and untreated natural IFN-gamma were equally neutralized and immunoprecipitated by GIF-1 antibody. In addition, a minor monomeric component of natural IFN-gamma with the m.w. of 15,500, which apparently lacks carbohydrate, was also recognized by antibody GIF-1. These results suggest that the discriminative recognition of natural...

From Gene to Protein: Translation Into Biotechnology, 1982

Publisher Summary This chapter describes an ELISA assay for detecting cell surface antigens on ad... more Publisher Summary This chapter describes an ELISA assay for detecting cell surface antigens on adherent cells. The effective use of monoclonal antibodies (mAb) in the analysis of cell surface antigens is dependent upon the availability of a rapid, reproducible, quantitative assay for their detection and characterization. To meet these requirements, an ELISA assay has been developed that allows for the detection of mAb recognizing antigens on the surface of viable, anchorage-dependent cells. Its utility in identifying the potential markers of human sarcoma cells has been tested. Therefore, ELISA is a rapid, reproducible, quantitative assay for screening and characterizing mAb. This assay is useful for identifying cell surface antigens in their native unfixed state.

The Journal of Immunology

Preparations of human interferon (HuIFN) immune (gamma) (2 X 10(7) units/mg protein), HuIFN leuko... more Preparations of human interferon (HuIFN) immune (gamma) (2 X 10(7) units/mg protein), HuIFN leukocyte (alpha) (1.4 X 10(8) units/mg protein) and HuIFN fibroblasts (beta) (10(6) U/mg protein) were assessed for their influence on colony formation of human hematopoietic progenitor cells: colony forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), burst forming unit-erythroid (BFU-E), day 7 colony forming unit granulocyte-macrophage (CFU-GM) and day 14 CFU-GM. Colony formation by CFU-GEMM and BFU-E was suppressed equally by the three preparations of HuIFN, but colony formation by CFU-GM was suppressed differentially. CFU-GM were, on the whole, more responsive to HuIFN gamma than HuIFN alpha, and HuIFN beta was least effective. HuIFN alpha, but not HuIFN gamma or HuIFN beta, suppressed colony formation from CFU-GM without also suppressing the total number of colonies plus clusters. This was due to an increase in the numbers of clusters formed in the presence of HuIF...

Dr. Feit and Dr. Adams answer questions from the audience

Dr. Feit briefly explains Jewish Law and how it governs Jewish thought and action

Cancer Letters, 1993

Introduction S,, a heterophile antigen present on human sarcoma cell lines in culture, has been p... more Introduction S,, a heterophile antigen present on human sarcoma cell lines in culture, has been previously defined by this laboratory [ 1,2]. This antigen is also present in guinea-pig kidney. Purification of the antigen to homogeneity has now been achieved by a combination of ammonium sulfate fractionation, DEAE-cellulose, sephadex, high pressure liquid chromatography and affinity chromotography. S, is a monomeric protein of 70 000 Da, as indicated by the presence of a single band on SDS-PAGE. Amino acid analysis demonstrates the prevalence of glycine, lysine and glutamic acid. Aspartic acid was found to be the N-terminal residue with further sequence of glycine-valinealanine-glutamic acid (gly-val-ala-glut).

Annals of the New York Academy of Sciences, 1975

Annals of the New York Academy of Sciences, 1976

International Journal of Immunopharmacology, 1982

Carcinoembryonic antigen (CEA) is an important tumor marker, associated with many neoplasms and m... more Carcinoembryonic antigen (CEA) is an important tumor marker, associated with many neoplasms and mainly with malignancies of the human digestive tract. A~ a consequence its ~nitoring serves as a crucial means in the follow-up of cancerous state. The ability to differentiate between different types of CEA may add another dimension to this diagnostic test. We approached this issue by analysis of the specificities of different anti-CEA monoclonal antibodies. Stable clones have been established from ten hybrido~as that produced anti-CEA antibodies. These ~noclonal antibodies (McAb) were found to differ in their ability to bind individual CEA preparations: Whereas three McAb's reacted identically with four different CEA's, the other seven exhibited different reactivities. The panel of McAb's, including the three identically reactive ones, differed in their capacity to stain CEA positive human cell lines derived from various tu~mrs. This finding is at present being evaluated for its potential as a diagnostic tool. Moreover, the antibody displaying the highest degree of cross-reactivity with all tested CEA preparations has been used for one step affinity purification of CEA, from either metastatic liver or culture fluids of different established CEA-producing cell lines, for the purpose of their further characterization.

Infection and Immunity, 1974

Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast c... more Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast cells of Histoplasma capsulatum . Ribosomes from disrupted cells were isolated by differential centrifugation using sodium dodecyl sulfate. These preparations contained 55% protein and 45% ribonucleic acid and sedimented as a single peak with a sedimentation coefficient of 77 S on sucrose density gradient analysis. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intravenously with 8 × 10 6 yeast cells of H. capsulatum . Significant protection was induced by ribosomes and was greatly enhanced by adjuvants. Protection measured by 30-day survival compared favorably with the immunoprotection assessed by absence of lung lesions and negative spleen cultures. Treatment of ribosomes with ribonuclease before immunization reduced protection by 85%, whereas trypsin and Pronase reduced the protection by 50 to 55%. These findings indicate that both intact riboso...

The use of monoclonal antibodies to distinguish human sar coma from carcinoma cells has been expl... more The use of monoclonal antibodies to distinguish human sar coma from carcinoma cells has been explored. Spleen cells from a BALB/c mouse immunized with a human malignant fibrohistiocytoma were fused with cells of the mouse P3Ui plasmacytoma cell line. Antibodies were then screened for reactivity against human sarcoma and carcinoma cells growing in culture. This work has yielded 2 immunoglobulin G monoclonal antibodies VIE4 and VIF3 which, respectively, reacted with 85% (17 of 20) and 90% (18 of 20) of sarcoma lines tested but with none of eight carcinoma cell line preparations. Reactivity against normal fibroblasts was also demonstrated. By immunofluorescence, the antigens detected by the two antibodies appear to have distinc tive intracellular distributions. Immunoprecipitation with VIF3 has shown that it is detecting a protein with a molecular weight of 70,000. When tested against pathological frozen tissue sections, VIF3 reacted with four of 11 and VIE4 with three of 11 human sarc...

I would like to address myself to certain aspects of the interplay between Torah and science. Whe... more I would like to address myself to certain aspects of the interplay between Torah and science. When I deal with science, I shall be discussing biology, the branch of science with which I am most familiar; and when I deal with scientific theories, I shall be referring to the theory of evolution because of its importance and centrality in modern biology. However, I would like to emphasize that these are but models. The lessons to be learned, if any, will apply to other sciences and theories as well. Torah and contemporary science interact at many levels. I intend to define three levels of interaction and to examine what can be learned from an analysis of each of them. They are: (1) methodology; (2) substance or fact; and (3) hashkafah, or world-view.

Cancer, Sep 1, 1985

Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and re... more Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and reacting with connective tissue differentiation antigens were evaluated for their interaction with tissues obtained from patients with classic Kaposi's sarcoma. Biopsy was performed on active neoplastic lesions from the skin of 26 patients, frozen sections were prepared, and the binding of the McAbs was tested using the indirect immunofluorescence assay. Clinically uninvolved skin from the same patients as well as skin and muscle from eight non-cancer patients were treated similarly and served as controls. McAbs IXG11, 23H7, IIIE5, and 15G5 interacted strongly with the Kaposi's sarcoma lesions and weakly with the uninvolved skin in 22 of 26 (84%), 23 of 26 (88%), 12 of 14 (85%), and 1 of 6 (16%) of the patients, respectively. IXG11, 23H7, and IIIE5 interacted weakly with the skin of seven of eight non-cancer patients. McAb 15G5 was found to bind strongly to tumor lesions, to the respective uninvolved skin in four of five Kaposi's sarcoma patients, and also to skin and connective tissues of muscle from non-cancer patients. The mode of interaction was morphologically different for each McAb. It is suggested that McAbs IXG11, 23H7 and IIIE5 identify markers whose expression is markedly increased in Kaposi's sarcoma lesions as compared with uninvolved skin of the same patients. These markers may serve as immunologic probes for the investigation of this neoplastic process.

Hybridoma, 1985

Flow cytometry of cellular DNA and RNA content was employed to determine DNA ploidy, proliferatio... more Flow cytometry of cellular DNA and RNA content was employed to determine DNA ploidy, proliferation, and RNA content of hybridoma cultures shortly after cell fusion and sequentially thereafter. The parental mouse myeloma cell line P3UI was characterized by tetraploid DNA content, S-phase 50%, and high RNA, the parental mouse spleen cells by diploid DNA content, low proliferation, and low RNA content. Hybridoma cultures studied as early as 21 days after fusion were found to contain the sum of the parental cells' DNA content (hexaploid), or if less, more than that of the myeloma parental cells. Only one clone of 35 tested was shown to be hexaploid and the rest hypertetraploid or hyperpentaploid. Hybrid cell cultures were frequently found to contain a variable mixture of unfused parental cells. The high proliferation of hybridoma cells determined by flow cytometry indicates that these cells would eventually overgrow the parental cells. Flow cytometry also enabled an accurate estimat...

Cancer, Sep 1, 1985

Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and re... more Four monoclonal antibodies (McAbs) previously generated against human soft tissue sarcomas and reacting with connective tissue differentiation antigens were evaluated for their interaction with tissues obtained from patients with classic Kaposi's sarcoma. Biopsy was performed on active neoplastic lesions from the skin of 26 patients, frozen sections were prepared, and the binding of the McAbs was tested using the indirect immunofluorescence assay. Clinically uninvolved skin from the same patients as well as skin and muscle from eight non-cancer patients were treated similarly and served as controls. McAbs IXG11, 23H7, IIIE5, and 15G5 interacted strongly with the Kaposi's sarcoma lesions and weakly with the uninvolved skin in 22 of 26 (84%), 23 of 26 (88%), 12 of 14 (85%), and 1 of 6 (16%) of the patients, respectively. IXG11, 23H7, and IIIE5 interacted weakly with the skin of seven of eight non-cancer patients. McAb 15G5 was found to bind strongly to tumor lesions, to the respective uninvolved skin in four of five Kaposi's sarcoma patients, and also to skin and connective tissues of muscle from non-cancer patients. The mode of interaction was morphologically different for each McAb. It is suggested that McAbs IXG11, 23H7 and IIIE5 identify markers whose expression is markedly increased in Kaposi's sarcoma lesions as compared with uninvolved skin of the same patients. These markers may serve as immunologic probes for the investigation of this neoplastic process.

Natural Immunity and Cell Growth Regulation, Feb 1, 1986

In an effort to determine the effect of dexamethasone on hybridoma formation, spleen cells from B... more In an effort to determine the effect of dexamethasone on hybridoma formation, spleen cells from BALB/c mice hyperimmunized with sheep red blood cells (SRBC) were fused with mouse plasmacytoma cells (P3U1) in the presence of polyethylene glycol (PEG). Dexamethasone was added in decreasing doses (10(-3) to 10(-9) mM) to the hypoxanthine-aminopterin-thymide (HAT) medium immediately after the PEG-mediated cell fusion. 10(-3) mM of this steroid was found to inhibit markedly the number and size of hybridoma clones generated, while 10(-5) mM dexamethasone was shown to enhance hybridoma formation. The effect of 10(-3) mM dexamethasone was most pronounced when added immediately after fusion. When this dose was given 48 or 120 h after cell fusion, the extent of the inhibitory effect was less pronounced. High concentration of dexamethasone may also inhibit monoclonal antibody production by hybridomas once generated. An increase in the number of clones formed was observed when 10(-5) mM dexamethasone was added to HAT medium as well as an increase in the average colony size. Large clones were also observed with lower dexamethasone doses ranging from 10(-7) to 10(-9) mM. Possible mechanisms on the effect of dexamethasone on hybridoma formation are discussed.