Jean-pierre Kolb - Academia.edu (original) (raw)
Papers by Jean-pierre Kolb
Journal of Immunology, Jul 15, 1997
Transgene CD23 expression on lymphoid cells modulates IgE and IgG1 responses.
The Journal of Immunology
The spleen cell population of adult C3H/He mice injected with a single sublethal dose of cyclopho... more The spleen cell population of adult C3H/He mice injected with a single sublethal dose of cyclophosphamide (CY) has been analyzed. An initial phase of spleen atrophy is followed by a considerable hypertrophy, and a progressive return to normal. During the phase of spleen atrophy, both B and T cell compartments are depleted, as estimated by the percentages of cells killed by anti-Thy 1–2 and anti-Ig antisera plus complement. During the stage of regeneration, the percentage of Ig + cells increases rapidly, and at the peak of splenomegaly, the percentage of Ig + cells is high whereas almost no Thy 1–2 + cells are detectable. Progressively, the spleen cell content returns to the original values. In thymodeprived mice (nude mice and B mice) the percentage of null cells increases during the stage of regeneration, and B mice develop a large number of Ig +-bearing cells. Histologic examination shows that follicles (B-dependent areas) disappear 1 to 2 days before periarteriolar sheaths (T-dep...
Van WeyenberghWietzerbin, Aldina Barral, Manoel Barral-Netto and JohanSilva, Almerio Noronha, Jea... more Van WeyenberghWietzerbin, Aldina Barral, Manoel Barral-Netto and JohanSilva, Almerio Noronha, Jean-Pierre Kolb, Juana Ricardo Khouri, Andre Bafica, Maria da Purificacao Pereirahttp://www.jimmunol.org/content/182/4/2525doi: 10.4049/jimmunol.0802860J Immunol€2009; 182:2525-2531; ;Referenceshttp://www.jimmunol.org/content/182/4/2525.full#ref-list-1This article cites 50 articles, 19 of which you can access for free at: Subscriptionshttp://jimmunol.org/subscriptionsInformation about subscribing to The Journal of Immunology is online at: Permissionshttp://www.aai.org/ji/copyright.htmlSubmit copyright permission requests at: Email Alertshttp://jimmunol.org/cgi/alerts/etocReceive free email-alerts when new articles cite this article. Sign up at:
Blood, 1998
We have investigated the interleukin-12 (IL-12) and tumor necrosis factor- (TNF)-induced regula... more We have investigated the interleukin-12 (IL-12) and tumor necrosis factor- (TNF)-induced regulation of human natural killer (NK) cell function and their relationship with nitric oxide (NO) generation. We demonstrate that both cytokines were efficient to trigger the transcription of the inducible nitric oxide synthase (iNOS) mRNA, as detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Western blot analysis and intracytoplasmic fluorescence showed that iNOS protein was also induced by both cytokines. However, our data indicate that NO does not play a significant role in the effector phase of the cytotoxic activity mediated by NK-stimulated cells, inasmuch as the lytic activity was not affected in the presence of specific NO synthase inhibitors. When aminoguanidine (AMG), an inhibitor of iNOS, was added during the afferent phase of NK stimulation with IL-12 and TNF, a subsequent increase in the lytic potential of the effector cells towards the NK-sensitive target c...
Blood, 1989
Hairy cells are stimulated to DNA synthesis by low molecular weight B cell growth factor (LMW-BCG... more Hairy cells are stimulated to DNA synthesis by low molecular weight B cell growth factor (LMW-BCGF) and this proliferative response is suppressed by interferon (IFN)-alpha, both in vitro and in vivo. The suggestion that the CD23 molecule (Fc epsilon II receptor) might be involved in the signalling pathway of LMW-BCGF prompted us to study the expression of this molecule on hairy cells and its modulation by IFN- alpha. By flow cytometry and direct binding experiments with anti CD23 monoclonal antibodies, the presence of the CD23 antigen was detected in 7 of 12 cases tested, on variable percentages of cells, ranging from low to medium expression. In vitro incubation of hairy cells with IFN- alpha, which elicits a suppression of the proliferative response of these cells to LMW-BCGF, induced a parallel significant reduction of CD23 expression in only three cases. Similarly, a transient in vivo decrease of CD23 expression, concommitant with an inhibition of the LMW- BCGF response, could b...
JNCI: Journal of the National Cancer Institute, 1974
Journal of Leukocyte Biology, 1995
Transduction through FcR2/CD23 was analyzed in normal human monocytes using immunoglobulin E (IgE... more Transduction through FcR2/CD23 was analyzed in normal human monocytes using immunoglobulin E (IgE)-anti-IgE immune complexes (IgE ICs) and monoclonal antibodies (mAbs) to CD23. Anti-CD23 mAb and IgE IC triggered a time-dependent increase in cGMP and cAMP in interleukin-4–preincubated (CD23+) but not in unstimulated (CD23-) monocytes. Maximal cGMP and cAMP accumulations were observed 10 and 20 min, respectively, after the onset of CD23 ligation. The increase in cGMP was inhibited with Nω-monomethyl-l-arginine (L-NMMA), which also partially affected cAMP accumulation. Addition of an anti-CD23 mAb Fab fragment inhibited the IgE IC– and the anti-CD23 mAb–induced cGMP and cAMP accumulation, confirming the engagement of CD23. In addition, IgE IC and anti-CD23 mAb induced, at least in some donors, a production of nitrite that was inhibited in the presence of L-NMMA. Taken together, these findings suggest a possible involvement of the nitric oxide synthase pathway in IgE IC–mediated activat...
JNCI: Journal of the National Cancer Institute, 1976
Suppressor cells were demonstrated in the spleens of C3H/He mice carrying 3-methylcholantrene-ind... more Suppressor cells were demonstrated in the spleens of C3H/He mice carrying 3-methylcholantrene-induced fibrosarcomas. These cells inhibited the in vitro reactivity of normal lymphocytes to T- and B-cell mitogens. They disappeared within a few days after the tumor was surgically removed. Pretreatment of spleen cells (ScC) from tumor-bearing (TB) mice with either iron and a nagnet, antiserum against Thy 1.2 antigen plus complement, or antiserum against immunoglobulin plus complement demonstrated that the suppressor cells were adherent, non-T-cells bearing immunoglobulin at their surfaces. The suppressive effect could still be demonstrated by addition of SpC from TB mice 24 or 48 hours after phytohemagglutinin stimulation of normal SpC, SpC from TB C3H/He mice inhibited mitogen-induced stimulation of both C3H/He and DBA/2 lymphocytes. In T-cell-deprived TB C3H/He mice, suppressor cells were also observed and had the same characteristics as those in non-T-cell-deprived mice. In nude mice, however, although suppressor cells were active, they were not adherent and did not bear immunoglobulin at their surfaces. The existence of these suppressor cells may be one reason why the immune system of TB animals is unable to reject the tumor.
JNCI: Journal of the National Cancer Institute, 1974
1. J Natl Cancer Inst. 1974 Mar;52(3):723-7. Tumor-associated antigen (TAA) and anti-TAA antibodi... more 1. J Natl Cancer Inst. 1974 Mar;52(3):723-7. Tumor-associated antigen (TAA) and anti-TAA antibodies in the serum of BALB-c mice with plasmacytomas. Kolb JP, Poupon MF, Lespinats G. PMID: 4826560 [PubMed - indexed for MEDLINE]. MeSH Terms: ...
Journal of Interferon Research, 1985
European cytokine network
The early events following the ligation of interleukin-4 (IL-4) to the plasmacytoma cell line RPM... more The early events following the ligation of interleukin-4 (IL-4) to the plasmacytoma cell line RPMI-8226 were analysed as a model of action for this interleukin on differentiated cells of the B lymphocyte lineage. The addition of recombinant IL-4 to these cells resulted in an increase of the intracytoplasmic free calcium concentration [Ca2+]i, but in contrast to normal B cells, this increase was mostly due to a calcium influx rather than to a mobilization from endoplasmic reticulum stores. IL-4 was also found to trigger cAMP accumulation in RPMI-8226 cells, with kinetics similar to that which has been described for normal resting human B lymphocytes. However, in contrast to normal B cells, IL-4 did not increase CD23 membrane expression on RPMI-8226 cells. But after incubation with high concentrations of IL-4, soluble CD23 (sCD23/IgE-BF) could be detected in the supernatant of these cells. In addition, the proliferation of RPMI-8226 cells was only moderately affected by IL-4. The expr...
Immunology, 1993
The early events triggered in interleukin-4 (IL-4)-stimulated U937 cells by ligation of CD23/Fc e... more The early events triggered in interleukin-4 (IL-4)-stimulated U937 cells by ligation of CD23/Fc epsilon RII with specific monoclonal antibodies (mAb) were analysed, as a model of the action of this molecule on the differentiation of promonocytic cells. As well as IL-4-activated human monocytes, addition of anti-CD23 mAb to IL-4-treated U937 cells triggered cAMP accumulation but did not evoke significant polyphosphoinositide hydrolysis. However, by a microspectrofluorometric technique allowing single cell analysis, anti-CD23 mAb was found to elicit calcium mobilization in these cells. In addition, the treatment induced phenotypic alterations in these cells, as evidenced by the acquisition of the monocyte marker CD14 and the increase of the alpha-chain (CD11a) and of the common beta-chain (CD18) of the leucocyte function-associated antigen 1 (LFA-1) family antigens. Although weaker than in monocytes, CD23 ligation evoked a small secretion of the pro-inflammatory mediators IL-6 and thr...
Research in Immunology, 1994
Leishmania brasiliensis causes cutaneous leishmaniasis (CL) in humans. During this infection, a v... more Leishmania brasiliensis causes cutaneous leishmaniasis (CL) in humans. During this infection, a variety of inflammatory mediators are produced by T cells and monocytes/macrophages. In the present study, we analysed serum IgE levels and their correlation with in situ expression of the low affinity receptor for IgE (Fc epsilon RII/CD23) in patients infected with L. brasiliensis before and following therapy. These analyses were compared to in situ expression of tumour necrosis factor-alpha (TNF alpha), interleukin 3 (IL3), interferon-gamma (IFN gamma) and IL4. Disease-free individuals from the same endemic area sensitized with L. brasiliensis antigens were also included in this work. Our data indicate that during infection, serum levels of IgE and TNF alpha increased and correlated with elevated in situ expression of CD23, IL4 and TNF alpha mRNA. This expression disappeared following successful treatment, but persisted in patients resistant to anti-leishmania therapy. Patients resistant to therapy differed from other cases by a dramatic decrease in their in vivo expression of IFN gamma protein. Analysis of CD23 function in purified human monocytes indicated that this antigen mediates IgE/anti-IgE-dependent TNF alpha production. These data suggest a possible in vivo role of CD23 in acute immune responses in human CL.
Leukemia, 1989
Hairy cells are classified as B cell tumors at a preplasma cell stage of differentiation and are ... more Hairy cells are classified as B cell tumors at a preplasma cell stage of differentiation and are believed to represent cells undergoing a switch process. These cells are stimulated in vitro to DNA synthesis and multiplication in the presence of the lymphokine LMW-BCGF. We have tested the level of expression on these cells of the newly described B8.7 activation marker which has been reported to be associated with the capacity of various B cells to respond to LMW-BCGF. The presence of this marker has been readily detected on the hairy cells of 10 of the 12 patients tested in this study; interestingly, for one of the negative cases, the tumor cells were unable to proliferate in response to LMW-BCGF. As on normal B cells, a marked inhibition of the LMW-BCGF dependent response could be achieved in the presence of a monoclonal anti-B8.7 antibody, sustaining the proposal that the B8.7 molecule is involved in the signaling pathway of this growth factor. IFN-alpha is highly efficient in the ...
Leukemia, 1987
Hairy cell leukemia (HCL) is a pre-plasma B cell tumor which responds to interferon (IFN)-alpha t... more Hairy cell leukemia (HCL) is a pre-plasma B cell tumor which responds to interferon (IFN)-alpha therapy. In vitro, B cell growth factor (BCGF) can induce proliferation of hairy cells. We have investigated the effect of in vitro and in vivo treatments with different recombinant IFN on the capacity of hairy cells to proliferate in response to human BCGF. In vitro treatment of leukemic cells from HCL patients with recombinant IFN-alpha-2 (5/5 cases) or IFN-beta (4/5 cases) resulted in a marked inhibition of the BCGF-dependent response. This suppressive effect was obtained with IFN concentrations of 1000, 100 IU/ml, and even occasionally 10 IU/ml. In contrast, no such inhibition was observed with IFN-gamma, despite the presence of specific IFN-gamma receptors on hairy cells at densities similar to receptors for IFN-alpha/beta. The IFN-alpha-induced suppression of the proliferative response of hairy cells to BCGF was also observed in vivo in two patients within 6-12 hr after administrati...
Proceedings of the National Academy of Sciences, 1982
Purified human native third component of complement, C3, was found to inhibit in vitro natural ki... more Purified human native third component of complement, C3, was found to inhibit in vitro natural killer (NK) cell cytotoxicity in both mouse and human systems. The effect was dose and time dependent, a 50% inhibition being reached with 190 nM C3 (35 micrograms/ml) added during the NK assay or after a 30-min preincubation of the effector cells with this C3 concentration. C3 was shown to act at the effector-cell population level because pretreatment of the target cells did not modify the NK lysis. The inhibition was not due to general cytotoxicity nor to cell agglutination. Moreover, another in vitro cytotoxicity system (represented by alloreactive cytotoxic lymphocytes) was not affected by purified C3. Structural analysis of the active part of the C3 molecule shows that the C3-induced inhibition is supported by the C3a fragment. Release of carboxyl-terminal arginine residue by carboxypeptidase B, converting C3a into des-Arg77-C3a, did not alter the inhibitory effect displayed by this f...
Journal of Immunology, Jul 15, 1997
Transgene CD23 expression on lymphoid cells modulates IgE and IgG1 responses.
The Journal of Immunology
The spleen cell population of adult C3H/He mice injected with a single sublethal dose of cyclopho... more The spleen cell population of adult C3H/He mice injected with a single sublethal dose of cyclophosphamide (CY) has been analyzed. An initial phase of spleen atrophy is followed by a considerable hypertrophy, and a progressive return to normal. During the phase of spleen atrophy, both B and T cell compartments are depleted, as estimated by the percentages of cells killed by anti-Thy 1–2 and anti-Ig antisera plus complement. During the stage of regeneration, the percentage of Ig + cells increases rapidly, and at the peak of splenomegaly, the percentage of Ig + cells is high whereas almost no Thy 1–2 + cells are detectable. Progressively, the spleen cell content returns to the original values. In thymodeprived mice (nude mice and B mice) the percentage of null cells increases during the stage of regeneration, and B mice develop a large number of Ig +-bearing cells. Histologic examination shows that follicles (B-dependent areas) disappear 1 to 2 days before periarteriolar sheaths (T-dep...
Van WeyenberghWietzerbin, Aldina Barral, Manoel Barral-Netto and JohanSilva, Almerio Noronha, Jea... more Van WeyenberghWietzerbin, Aldina Barral, Manoel Barral-Netto and JohanSilva, Almerio Noronha, Jean-Pierre Kolb, Juana Ricardo Khouri, Andre Bafica, Maria da Purificacao Pereirahttp://www.jimmunol.org/content/182/4/2525doi: 10.4049/jimmunol.0802860J Immunol€2009; 182:2525-2531; ;Referenceshttp://www.jimmunol.org/content/182/4/2525.full#ref-list-1This article cites 50 articles, 19 of which you can access for free at: Subscriptionshttp://jimmunol.org/subscriptionsInformation about subscribing to The Journal of Immunology is online at: Permissionshttp://www.aai.org/ji/copyright.htmlSubmit copyright permission requests at: Email Alertshttp://jimmunol.org/cgi/alerts/etocReceive free email-alerts when new articles cite this article. Sign up at:
Blood, 1998
We have investigated the interleukin-12 (IL-12) and tumor necrosis factor- (TNF)-induced regula... more We have investigated the interleukin-12 (IL-12) and tumor necrosis factor- (TNF)-induced regulation of human natural killer (NK) cell function and their relationship with nitric oxide (NO) generation. We demonstrate that both cytokines were efficient to trigger the transcription of the inducible nitric oxide synthase (iNOS) mRNA, as detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Western blot analysis and intracytoplasmic fluorescence showed that iNOS protein was also induced by both cytokines. However, our data indicate that NO does not play a significant role in the effector phase of the cytotoxic activity mediated by NK-stimulated cells, inasmuch as the lytic activity was not affected in the presence of specific NO synthase inhibitors. When aminoguanidine (AMG), an inhibitor of iNOS, was added during the afferent phase of NK stimulation with IL-12 and TNF, a subsequent increase in the lytic potential of the effector cells towards the NK-sensitive target c...
Blood, 1989
Hairy cells are stimulated to DNA synthesis by low molecular weight B cell growth factor (LMW-BCG... more Hairy cells are stimulated to DNA synthesis by low molecular weight B cell growth factor (LMW-BCGF) and this proliferative response is suppressed by interferon (IFN)-alpha, both in vitro and in vivo. The suggestion that the CD23 molecule (Fc epsilon II receptor) might be involved in the signalling pathway of LMW-BCGF prompted us to study the expression of this molecule on hairy cells and its modulation by IFN- alpha. By flow cytometry and direct binding experiments with anti CD23 monoclonal antibodies, the presence of the CD23 antigen was detected in 7 of 12 cases tested, on variable percentages of cells, ranging from low to medium expression. In vitro incubation of hairy cells with IFN- alpha, which elicits a suppression of the proliferative response of these cells to LMW-BCGF, induced a parallel significant reduction of CD23 expression in only three cases. Similarly, a transient in vivo decrease of CD23 expression, concommitant with an inhibition of the LMW- BCGF response, could b...
JNCI: Journal of the National Cancer Institute, 1974
Journal of Leukocyte Biology, 1995
Transduction through FcR2/CD23 was analyzed in normal human monocytes using immunoglobulin E (IgE... more Transduction through FcR2/CD23 was analyzed in normal human monocytes using immunoglobulin E (IgE)-anti-IgE immune complexes (IgE ICs) and monoclonal antibodies (mAbs) to CD23. Anti-CD23 mAb and IgE IC triggered a time-dependent increase in cGMP and cAMP in interleukin-4–preincubated (CD23+) but not in unstimulated (CD23-) monocytes. Maximal cGMP and cAMP accumulations were observed 10 and 20 min, respectively, after the onset of CD23 ligation. The increase in cGMP was inhibited with Nω-monomethyl-l-arginine (L-NMMA), which also partially affected cAMP accumulation. Addition of an anti-CD23 mAb Fab fragment inhibited the IgE IC– and the anti-CD23 mAb–induced cGMP and cAMP accumulation, confirming the engagement of CD23. In addition, IgE IC and anti-CD23 mAb induced, at least in some donors, a production of nitrite that was inhibited in the presence of L-NMMA. Taken together, these findings suggest a possible involvement of the nitric oxide synthase pathway in IgE IC–mediated activat...
JNCI: Journal of the National Cancer Institute, 1976
Suppressor cells were demonstrated in the spleens of C3H/He mice carrying 3-methylcholantrene-ind... more Suppressor cells were demonstrated in the spleens of C3H/He mice carrying 3-methylcholantrene-induced fibrosarcomas. These cells inhibited the in vitro reactivity of normal lymphocytes to T- and B-cell mitogens. They disappeared within a few days after the tumor was surgically removed. Pretreatment of spleen cells (ScC) from tumor-bearing (TB) mice with either iron and a nagnet, antiserum against Thy 1.2 antigen plus complement, or antiserum against immunoglobulin plus complement demonstrated that the suppressor cells were adherent, non-T-cells bearing immunoglobulin at their surfaces. The suppressive effect could still be demonstrated by addition of SpC from TB mice 24 or 48 hours after phytohemagglutinin stimulation of normal SpC, SpC from TB C3H/He mice inhibited mitogen-induced stimulation of both C3H/He and DBA/2 lymphocytes. In T-cell-deprived TB C3H/He mice, suppressor cells were also observed and had the same characteristics as those in non-T-cell-deprived mice. In nude mice, however, although suppressor cells were active, they were not adherent and did not bear immunoglobulin at their surfaces. The existence of these suppressor cells may be one reason why the immune system of TB animals is unable to reject the tumor.
JNCI: Journal of the National Cancer Institute, 1974
1. J Natl Cancer Inst. 1974 Mar;52(3):723-7. Tumor-associated antigen (TAA) and anti-TAA antibodi... more 1. J Natl Cancer Inst. 1974 Mar;52(3):723-7. Tumor-associated antigen (TAA) and anti-TAA antibodies in the serum of BALB-c mice with plasmacytomas. Kolb JP, Poupon MF, Lespinats G. PMID: 4826560 [PubMed - indexed for MEDLINE]. MeSH Terms: ...
Journal of Interferon Research, 1985
European cytokine network
The early events following the ligation of interleukin-4 (IL-4) to the plasmacytoma cell line RPM... more The early events following the ligation of interleukin-4 (IL-4) to the plasmacytoma cell line RPMI-8226 were analysed as a model of action for this interleukin on differentiated cells of the B lymphocyte lineage. The addition of recombinant IL-4 to these cells resulted in an increase of the intracytoplasmic free calcium concentration [Ca2+]i, but in contrast to normal B cells, this increase was mostly due to a calcium influx rather than to a mobilization from endoplasmic reticulum stores. IL-4 was also found to trigger cAMP accumulation in RPMI-8226 cells, with kinetics similar to that which has been described for normal resting human B lymphocytes. However, in contrast to normal B cells, IL-4 did not increase CD23 membrane expression on RPMI-8226 cells. But after incubation with high concentrations of IL-4, soluble CD23 (sCD23/IgE-BF) could be detected in the supernatant of these cells. In addition, the proliferation of RPMI-8226 cells was only moderately affected by IL-4. The expr...
Immunology, 1993
The early events triggered in interleukin-4 (IL-4)-stimulated U937 cells by ligation of CD23/Fc e... more The early events triggered in interleukin-4 (IL-4)-stimulated U937 cells by ligation of CD23/Fc epsilon RII with specific monoclonal antibodies (mAb) were analysed, as a model of the action of this molecule on the differentiation of promonocytic cells. As well as IL-4-activated human monocytes, addition of anti-CD23 mAb to IL-4-treated U937 cells triggered cAMP accumulation but did not evoke significant polyphosphoinositide hydrolysis. However, by a microspectrofluorometric technique allowing single cell analysis, anti-CD23 mAb was found to elicit calcium mobilization in these cells. In addition, the treatment induced phenotypic alterations in these cells, as evidenced by the acquisition of the monocyte marker CD14 and the increase of the alpha-chain (CD11a) and of the common beta-chain (CD18) of the leucocyte function-associated antigen 1 (LFA-1) family antigens. Although weaker than in monocytes, CD23 ligation evoked a small secretion of the pro-inflammatory mediators IL-6 and thr...
Research in Immunology, 1994
Leishmania brasiliensis causes cutaneous leishmaniasis (CL) in humans. During this infection, a v... more Leishmania brasiliensis causes cutaneous leishmaniasis (CL) in humans. During this infection, a variety of inflammatory mediators are produced by T cells and monocytes/macrophages. In the present study, we analysed serum IgE levels and their correlation with in situ expression of the low affinity receptor for IgE (Fc epsilon RII/CD23) in patients infected with L. brasiliensis before and following therapy. These analyses were compared to in situ expression of tumour necrosis factor-alpha (TNF alpha), interleukin 3 (IL3), interferon-gamma (IFN gamma) and IL4. Disease-free individuals from the same endemic area sensitized with L. brasiliensis antigens were also included in this work. Our data indicate that during infection, serum levels of IgE and TNF alpha increased and correlated with elevated in situ expression of CD23, IL4 and TNF alpha mRNA. This expression disappeared following successful treatment, but persisted in patients resistant to anti-leishmania therapy. Patients resistant to therapy differed from other cases by a dramatic decrease in their in vivo expression of IFN gamma protein. Analysis of CD23 function in purified human monocytes indicated that this antigen mediates IgE/anti-IgE-dependent TNF alpha production. These data suggest a possible in vivo role of CD23 in acute immune responses in human CL.
Leukemia, 1989
Hairy cells are classified as B cell tumors at a preplasma cell stage of differentiation and are ... more Hairy cells are classified as B cell tumors at a preplasma cell stage of differentiation and are believed to represent cells undergoing a switch process. These cells are stimulated in vitro to DNA synthesis and multiplication in the presence of the lymphokine LMW-BCGF. We have tested the level of expression on these cells of the newly described B8.7 activation marker which has been reported to be associated with the capacity of various B cells to respond to LMW-BCGF. The presence of this marker has been readily detected on the hairy cells of 10 of the 12 patients tested in this study; interestingly, for one of the negative cases, the tumor cells were unable to proliferate in response to LMW-BCGF. As on normal B cells, a marked inhibition of the LMW-BCGF dependent response could be achieved in the presence of a monoclonal anti-B8.7 antibody, sustaining the proposal that the B8.7 molecule is involved in the signaling pathway of this growth factor. IFN-alpha is highly efficient in the ...
Leukemia, 1987
Hairy cell leukemia (HCL) is a pre-plasma B cell tumor which responds to interferon (IFN)-alpha t... more Hairy cell leukemia (HCL) is a pre-plasma B cell tumor which responds to interferon (IFN)-alpha therapy. In vitro, B cell growth factor (BCGF) can induce proliferation of hairy cells. We have investigated the effect of in vitro and in vivo treatments with different recombinant IFN on the capacity of hairy cells to proliferate in response to human BCGF. In vitro treatment of leukemic cells from HCL patients with recombinant IFN-alpha-2 (5/5 cases) or IFN-beta (4/5 cases) resulted in a marked inhibition of the BCGF-dependent response. This suppressive effect was obtained with IFN concentrations of 1000, 100 IU/ml, and even occasionally 10 IU/ml. In contrast, no such inhibition was observed with IFN-gamma, despite the presence of specific IFN-gamma receptors on hairy cells at densities similar to receptors for IFN-alpha/beta. The IFN-alpha-induced suppression of the proliferative response of hairy cells to BCGF was also observed in vivo in two patients within 6-12 hr after administrati...
Proceedings of the National Academy of Sciences, 1982
Purified human native third component of complement, C3, was found to inhibit in vitro natural ki... more Purified human native third component of complement, C3, was found to inhibit in vitro natural killer (NK) cell cytotoxicity in both mouse and human systems. The effect was dose and time dependent, a 50% inhibition being reached with 190 nM C3 (35 micrograms/ml) added during the NK assay or after a 30-min preincubation of the effector cells with this C3 concentration. C3 was shown to act at the effector-cell population level because pretreatment of the target cells did not modify the NK lysis. The inhibition was not due to general cytotoxicity nor to cell agglutination. Moreover, another in vitro cytotoxicity system (represented by alloreactive cytotoxic lymphocytes) was not affected by purified C3. Structural analysis of the active part of the C3 molecule shows that the C3-induced inhibition is supported by the C3a fragment. Release of carboxyl-terminal arginine residue by carboxypeptidase B, converting C3a into des-Arg77-C3a, did not alter the inhibitory effect displayed by this f...