Marta Amaral - Academia.edu (original) (raw)

Papers by Marta Amaral

... Cindy L Carmack, 1 Marta Amaral-Melendez, 2 Edwin Boudreaux, 1 Phillip J. Brantley, 3,4 Glenn... more ... Cindy L Carmack, 1 Marta Amaral-Melendez, 2 Edwin Boudreaux, 1 Phillip J. Brantley, 3,4 Glenn N. Jones, 3 B. Don Franks, 2 and G. Tipton McKnight 3 ... IDepartment of Psychology, Louisiana State University, Baton Rouge, Louisiana 70803. ...

Assessment, 1995

Ample evidence suggests stress can have serious effects on both physical and mental health. This ... more Ample evidence suggests stress can have serious effects on both physical and mental health. This has motivated researchers to investigate which coping strategies lead to more adaptive responses. One such strategy receiving an increasing amount of attention is religious coping. However, the measurement of religious coping needs further development. The present study reports the development and preliminary reliability and validity studies of the Ways of Religious Coping Scale (WORCS). This scale is a self-report instrument for assessing the degree and kind of religious cognitions and behaviors people use to cope with stress. Results indicate the WORCS is psychometrically sound and may be a useful tool for future research in the area of religious coping.

Annals of Behavioral Medicine, 1999

This study examined exercise as a moderator of the stress-illness relation by exploring leisure p... more This study examined exercise as a moderator of the stress-illness relation by exploring leisure physical activity and aerobic fitness as "buffers" of the effects stress has on physical and psychological symptoms in a sample of 135 college students. Specifically, the goal was to provide information regarding the mechanisms by which

In the world, diabetes disease affects about 347 millions of people, according to the World Healt... more In the world, diabetes disease affects about 347 millions of people, according to the World Health Organization, (WHO). In the United States, this disease has increased from 5.6 millions in 1980 to 20.9 in 2011 (Centers for Disease Control, CDC, 2013). Moreover, the Hispanic group has the greatest rate of increase, specially puertorricans. In Puerto Rico, 2011, 13.5% of the adult population was diagnosed with diabetes. The development of cardiovascular and chronic kidney diseases, sometimes prematurely, is the most significant complications of the diabetes. Therefore, exploring alternative strategies that will help in the prevention of diabetes is of utmost importance. Physical activity/exercise can be used for primary and secondary prevention. Clinical investigations have shown the effectiveness of physical activity/exercise interventions in clinical outcomes in diabetics. However, these patients remain living a sedentary lifestyle. In this article, a description of a new strategy ...

BMC Public Health, 2014

Background: Physical inactivity is increasing among children and adolescents and may be contribut... more Background: Physical inactivity is increasing among children and adolescents and may be contributing to the increasing prevalence of overweight and obesity. This study examines physical activity and sedentary behavior patterns, and explores associations with individual, maternal, household, and community factors amongst rural South African adolescents. Methods: In 2009, 381 subjects, stratified by ages 11-12-years and 14-15-years, were randomly selected from 3511 children and adolescents who had participated in a growth survey two years previously. Weight and height were measured and self-reported Tanner pubertal stage was collected. A questionnaire quantifying frequency and duration of physical activity (PA) domains and sedentary time for the previous 12 months was administered. Moderate-vigorous physical activity (MVPA mins/wk) was calculated for time spent in school and club sport. Socio-demographic and other related data were included from the Agincourt health and socio-demographic system (HDSS). The Agincourt HDSS was established in 1992 and collects prospective data on the community living in the Agincourt sub-district of Mpumalanga Province in rural northeast South Africa. Results: Puberty, maternal education and socioeconomic status (SES) contributed significantly to the mulitiple linear regression model for sedentary behavior (R 2 = 0.199; adjusted R 2 = 0.139; p < 0.000), and sex, SES and maternal education contributed to the tobit regression model for school and club sport MVPA (p < 0.000). MVPA, calculated from school and club sport, was higher in boys than girls (p < 0.001), and informal activity was lower (boys: p < 0.05 and girls: p < 0.01) while sedentary time was higher (girls: p < 0.01) in the older than the younger groups. Ninety-two percent (92%) of the sample reported walking for transport. Conclusions: In this study of rural South African adolescent boys and girls, SES at the maternal, household and community level independently predicted time spent in sedentary behaviors, and school and club MVPA. This study provides local data that can be used to develop health promotion strategies specific to this community, and other similar communities in developing countries.

Comparative Immunology, Microbiology and Infectious Diseases, 2015

Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete ... more Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete the bacteria in their urine and can transmit the pathogen from animal to animal or animal to human. Thus, surveillance and monitoring systems for detection of new Leptospira serovars are important for the control of leptospirosis. Here, we report the isolation of a spirochete from a stillborn bovine foetus and its characterization by immunological and molecular techniques. A variable number tandem repeat profile using seven discriminatory primers identified the spirochete as belonging to species Leptospira interrogans serogroup Australis serovar Muenchen. A phenotypic analysis using monoclonal antibodies (mAbs) against leptospiral membrane-associated proteins confirmed the expression of important virulence and pathogenicity factors (LipL32 and LigBrep). Out of 120 reference sera tested, 22 positive (36.66%) and 9 negative (15%) also reacted with the new isolate. Furthermore, the serovar Muenchen isolate was virulent in hamster model. The animal inoculated developed acute lethal infection characterized by hepatic, pulmonary and renal lesions. Local isolates exhibited unique characteristics that differed from those of reference strains; therefore, isolation of leptospires is useful in the surveillance of local pathogenic serovars. In conclusion, the data obtained from this study can contribute to the epidemiological understanding and control of leptospirosis in southern Brazil.

BioMed Research International, 2014

Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act ... more Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act as mediators of pathogenesis, serodiagnostic antigens, and immunogens. Purified recombinant LigA protein is the most promising subunit vaccine candidate against leptospirosis reported to date, however, as purified proteins are weak immunogens the use of a potent adjuvant is essential for the success of LigA as a subunit vaccine. In the present study, we compared xanthan pv. pruni (strain 106), aluminium hydroxide (alhydrogel), and CpG ODN as adjuvants in a LigA subunit vaccine preparation. Xanthan gum is a high molecular weight extracellular polysaccharide produced by fermentation of Xanthomonas spp., a plant-pathogenic bacterium genus. Preparations containing xanthan induced a strong antibody response comparable to that observed when alhydrogel was used. Upon challenge with a virulent strain of L. interrogans serovar Copenhageni, significant protection (Fisher test, < 0.05) was observed in 100%, 100%, and 67% of hamsters immunized with rLigANI-xanthan, LigA-CpG-xanthan, and rLigANI-alhydrogel, respectively. Furthermore, xanthan did not cause cytotoxicity in Chinese hamster ovary (CHO) cells in vitro. The use of xanthan as an adjuvant is a novel alternative for enhancing the immunogenicity of vaccines against leptospirosis and possibly against other pathogens.

The Journal of Nutritional Biochemistry, 2014

The aim of this study was to investigate the protective effect of anthocyanins (ANT) on oxidative... more The aim of this study was to investigate the protective effect of anthocyanins (ANT) on oxidative and inflammatory parameters, as well as ion pump activities, in the pons of rats experimentally demyelinated with ethidium bromide (EB). Rats were divided in six groups: control, ANT 30 mg/kg, ANT 100 mg/kg, EB (0.1%), EB plus ANT 30 mg/kg and EB plus ANT 100 mg/kg. The EB cistern pons injection occurred on the first day. On day 7, there was a peak in the demyelination. During the 7 days, the animals were treated once per day with vehicle or ANT. It was observed that demyelination reduced Na(+),K(+)-ATPase and Ca(2+)-ATPase activities and increased 4-hydroxynonenal, malondialdehyde, protein carbonyl and NO2plus NO3 levels. In addition, a depletion of glutathione reduced level/nonprotein thiol content and a decrease in superoxide dismutase activity were also seen. The dose of 100 mg/kg showed a better dose-response to the protective effects. The demyelination did not affect the neuronal viability but did increase the inflammatory infiltrate (myeloperoxidase activity) followed by an elevation in interleukin (IL)-1β, IL-6, tumor necrosis factor-α and interferon-γ levels. ANT promoted a reduction in cellular infiltration and proinflammatory mediators. Furthermore, ANT restored the levels of IL-10. Luxol fast blue staining confirmed the loss of myelin in the EB group and the protective effect of ANT 100 mg/kg. In conclusion, this study was the first to show that ANT are able to restore ion pump activities and protect cellular components against the inflammatory and oxidative damages induced by demyelination.

Vaccine, 2007

The bacillus Calmette–Guerin (BCG), a live attenuated Mycobacterium bovis strain is considered a ... more The bacillus Calmette–Guerin (BCG), a live attenuated Mycobacterium bovis strain is considered a promising candidate as a vector system for delivery of foreign antigens to the immune system. The gene coding for the Leptospira interrogans external membrane protein ...

Journal of Equine Veterinary Science, 2011

During a routine trip to a horse slaughterhouse, we found bilateral ovarian teratoma. Macroscopic... more During a routine trip to a horse slaughterhouse, we found bilateral ovarian teratoma. Macroscopic findings were confirmed by the presence of hair, bones, and cartilage. Under microscopy, these tumors had mature foreign tissues as stratified squamous and ...

European Journal of Internal Medicine, 2011

BACKGROUND Tuberculosis is an infectious disease mainly caused by Mycobacterium tuberculosis that... more BACKGROUND Tuberculosis is an infectious disease mainly caused by Mycobacterium tuberculosis that health systems have been battled over time. Nowadays, it is still a big burden among various countries. The most affected are the immunosuppressed, the urban ...

European Journal of Internal Medicine, 2011

European Journal of Internal Medicine, 2010

European Journal of Internal Medicine, 2010

Background: Upper gastrointestinal bleeding is the severe complication of stress-related mucosal ... more Background: Upper gastrointestinal bleeding is the severe complication of stress-related mucosal disease in hospitalized patients. In intensive care units (ICU), risk factors are well defined and only mechanical ventilation and coagulopathy proved to be relevant for significant bleeding. On the contrary, in non-ICU settings there is no consensus about this issue. Nevertheless, omeprazole is still widely used in prophylaxis of bleeding. The objective of our study was to evaluate the relevance of stress-related mucosal disease bleeding in patients admitted to an internal medicine ward, and the role of omeprazole in its prophylaxis. Methods: We conducted a retrospective study in which we analysed consecutive patients who were admitted to our ward over a year. We recorded demographic characteristics of the patients, potential risk factors for stress-related mucosal disease (clinical data, laboratory, and medication), administration of prophylactic omeprazole, and total cost of this prophylaxis. Patients with active gastrointestinal bleeding on the admission were excluded. We recorded every upper gastrointestinal bleeding event with clinical relevance. Results: Five hundred and thirty-five patients, mean age 70 years, mean length of stay 9.6 ± 7.7 days; 140 (26.2%) patients were treated with 40 mg of omeprazole intravenously, 193 (36.1%) with 20 mg of omeprazole orally, and 202 (37.8%) patients had no prophylaxis. There was only one episode (0.2%) of clinically relevant bleeding. Conclusion: In patients admitted to an internal medicine ward, incidence of upper gastrointestinal bleeding as a complication of stress-related mucosal disease is low. We found that there is no advantage in prophylaxis with omeprazole.

Clinical and Vaccine Immunology, 2013

The leptospiral immunoglobulin-like (Lig) proteins LigA and LigB possess immunoglobulin-like doma... more The leptospiral immunoglobulin-like (Lig) proteins LigA and LigB possess immunoglobulin-like domains with 90-amino-acid repeats and are adhesion molecules involved in pathogenicity. They are conserved in pathogenic Leptospira spp. and thus are of interest for use as serodiagnostic antigens and in recombinant vaccine formulations. The N-terminal amino acid sequences of the LigA and LigB proteins are identical, but the C-terminal sequences vary. In this study, we evaluated the protective potential of five truncated forms of LigA and LigB proteins from Leptospira interrogans serovar Canicola as DNA vaccines using the pTARGET mammalian expression vector. Hamsters immunized with the DNA vaccines were subjected to a heterologous challenge with L. interrogans serovar Copenhageni strain Spool via the intraperitoneal route. Immunization with a DNA vaccine encoding LigBrep resulted in the survival of 5/8 (62.5%) hamsters against lethal infection (P < 0.05). None of the control hamsters or animals immunized with the other vaccine preparations survived. The vaccine induced an IgG antibody response and, additionally, conferred sterilizing immunity in 80% of the surviving animals. Our results indicate that the LigBrep DNA vaccine is a promising candidate for inclusion in a protective leptospiral vaccine.

... Cindy L Carmack, 1 Marta Amaral-Melendez, 2 Edwin Boudreaux, 1 Phillip J. Brantley, 3,4 Glenn... more ... Cindy L Carmack, 1 Marta Amaral-Melendez, 2 Edwin Boudreaux, 1 Phillip J. Brantley, 3,4 Glenn N. Jones, 3 B. Don Franks, 2 and G. Tipton McKnight 3 ... IDepartment of Psychology, Louisiana State University, Baton Rouge, Louisiana 70803. ...

Assessment, 1995

Ample evidence suggests stress can have serious effects on both physical and mental health. This ... more Ample evidence suggests stress can have serious effects on both physical and mental health. This has motivated researchers to investigate which coping strategies lead to more adaptive responses. One such strategy receiving an increasing amount of attention is religious coping. However, the measurement of religious coping needs further development. The present study reports the development and preliminary reliability and validity studies of the Ways of Religious Coping Scale (WORCS). This scale is a self-report instrument for assessing the degree and kind of religious cognitions and behaviors people use to cope with stress. Results indicate the WORCS is psychometrically sound and may be a useful tool for future research in the area of religious coping.

Annals of Behavioral Medicine, 1999

This study examined exercise as a moderator of the stress-illness relation by exploring leisure p... more This study examined exercise as a moderator of the stress-illness relation by exploring leisure physical activity and aerobic fitness as "buffers" of the effects stress has on physical and psychological symptoms in a sample of 135 college students. Specifically, the goal was to provide information regarding the mechanisms by which

In the world, diabetes disease affects about 347 millions of people, according to the World Healt... more In the world, diabetes disease affects about 347 millions of people, according to the World Health Organization, (WHO). In the United States, this disease has increased from 5.6 millions in 1980 to 20.9 in 2011 (Centers for Disease Control, CDC, 2013). Moreover, the Hispanic group has the greatest rate of increase, specially puertorricans. In Puerto Rico, 2011, 13.5% of the adult population was diagnosed with diabetes. The development of cardiovascular and chronic kidney diseases, sometimes prematurely, is the most significant complications of the diabetes. Therefore, exploring alternative strategies that will help in the prevention of diabetes is of utmost importance. Physical activity/exercise can be used for primary and secondary prevention. Clinical investigations have shown the effectiveness of physical activity/exercise interventions in clinical outcomes in diabetics. However, these patients remain living a sedentary lifestyle. In this article, a description of a new strategy ...

BMC Public Health, 2014

Background: Physical inactivity is increasing among children and adolescents and may be contribut... more Background: Physical inactivity is increasing among children and adolescents and may be contributing to the increasing prevalence of overweight and obesity. This study examines physical activity and sedentary behavior patterns, and explores associations with individual, maternal, household, and community factors amongst rural South African adolescents. Methods: In 2009, 381 subjects, stratified by ages 11-12-years and 14-15-years, were randomly selected from 3511 children and adolescents who had participated in a growth survey two years previously. Weight and height were measured and self-reported Tanner pubertal stage was collected. A questionnaire quantifying frequency and duration of physical activity (PA) domains and sedentary time for the previous 12 months was administered. Moderate-vigorous physical activity (MVPA mins/wk) was calculated for time spent in school and club sport. Socio-demographic and other related data were included from the Agincourt health and socio-demographic system (HDSS). The Agincourt HDSS was established in 1992 and collects prospective data on the community living in the Agincourt sub-district of Mpumalanga Province in rural northeast South Africa. Results: Puberty, maternal education and socioeconomic status (SES) contributed significantly to the mulitiple linear regression model for sedentary behavior (R 2 = 0.199; adjusted R 2 = 0.139; p < 0.000), and sex, SES and maternal education contributed to the tobit regression model for school and club sport MVPA (p < 0.000). MVPA, calculated from school and club sport, was higher in boys than girls (p < 0.001), and informal activity was lower (boys: p < 0.05 and girls: p < 0.01) while sedentary time was higher (girls: p < 0.01) in the older than the younger groups. Ninety-two percent (92%) of the sample reported walking for transport. Conclusions: In this study of rural South African adolescent boys and girls, SES at the maternal, household and community level independently predicted time spent in sedentary behaviors, and school and club MVPA. This study provides local data that can be used to develop health promotion strategies specific to this community, and other similar communities in developing countries.

Comparative Immunology, Microbiology and Infectious Diseases, 2015

Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete ... more Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete the bacteria in their urine and can transmit the pathogen from animal to animal or animal to human. Thus, surveillance and monitoring systems for detection of new Leptospira serovars are important for the control of leptospirosis. Here, we report the isolation of a spirochete from a stillborn bovine foetus and its characterization by immunological and molecular techniques. A variable number tandem repeat profile using seven discriminatory primers identified the spirochete as belonging to species Leptospira interrogans serogroup Australis serovar Muenchen. A phenotypic analysis using monoclonal antibodies (mAbs) against leptospiral membrane-associated proteins confirmed the expression of important virulence and pathogenicity factors (LipL32 and LigBrep). Out of 120 reference sera tested, 22 positive (36.66%) and 9 negative (15%) also reacted with the new isolate. Furthermore, the serovar Muenchen isolate was virulent in hamster model. The animal inoculated developed acute lethal infection characterized by hepatic, pulmonary and renal lesions. Local isolates exhibited unique characteristics that differed from those of reference strains; therefore, isolation of leptospires is useful in the surveillance of local pathogenic serovars. In conclusion, the data obtained from this study can contribute to the epidemiological understanding and control of leptospirosis in southern Brazil.

BioMed Research International, 2014

Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act ... more Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act as mediators of pathogenesis, serodiagnostic antigens, and immunogens. Purified recombinant LigA protein is the most promising subunit vaccine candidate against leptospirosis reported to date, however, as purified proteins are weak immunogens the use of a potent adjuvant is essential for the success of LigA as a subunit vaccine. In the present study, we compared xanthan pv. pruni (strain 106), aluminium hydroxide (alhydrogel), and CpG ODN as adjuvants in a LigA subunit vaccine preparation. Xanthan gum is a high molecular weight extracellular polysaccharide produced by fermentation of Xanthomonas spp., a plant-pathogenic bacterium genus. Preparations containing xanthan induced a strong antibody response comparable to that observed when alhydrogel was used. Upon challenge with a virulent strain of L. interrogans serovar Copenhageni, significant protection (Fisher test, < 0.05) was observed in 100%, 100%, and 67% of hamsters immunized with rLigANI-xanthan, LigA-CpG-xanthan, and rLigANI-alhydrogel, respectively. Furthermore, xanthan did not cause cytotoxicity in Chinese hamster ovary (CHO) cells in vitro. The use of xanthan as an adjuvant is a novel alternative for enhancing the immunogenicity of vaccines against leptospirosis and possibly against other pathogens.

The Journal of Nutritional Biochemistry, 2014

The aim of this study was to investigate the protective effect of anthocyanins (ANT) on oxidative... more The aim of this study was to investigate the protective effect of anthocyanins (ANT) on oxidative and inflammatory parameters, as well as ion pump activities, in the pons of rats experimentally demyelinated with ethidium bromide (EB). Rats were divided in six groups: control, ANT 30 mg/kg, ANT 100 mg/kg, EB (0.1%), EB plus ANT 30 mg/kg and EB plus ANT 100 mg/kg. The EB cistern pons injection occurred on the first day. On day 7, there was a peak in the demyelination. During the 7 days, the animals were treated once per day with vehicle or ANT. It was observed that demyelination reduced Na(+),K(+)-ATPase and Ca(2+)-ATPase activities and increased 4-hydroxynonenal, malondialdehyde, protein carbonyl and NO2plus NO3 levels. In addition, a depletion of glutathione reduced level/nonprotein thiol content and a decrease in superoxide dismutase activity were also seen. The dose of 100 mg/kg showed a better dose-response to the protective effects. The demyelination did not affect the neuronal viability but did increase the inflammatory infiltrate (myeloperoxidase activity) followed by an elevation in interleukin (IL)-1β, IL-6, tumor necrosis factor-α and interferon-γ levels. ANT promoted a reduction in cellular infiltration and proinflammatory mediators. Furthermore, ANT restored the levels of IL-10. Luxol fast blue staining confirmed the loss of myelin in the EB group and the protective effect of ANT 100 mg/kg. In conclusion, this study was the first to show that ANT are able to restore ion pump activities and protect cellular components against the inflammatory and oxidative damages induced by demyelination.

Vaccine, 2007

The bacillus Calmette–Guerin (BCG), a live attenuated Mycobacterium bovis strain is considered a ... more The bacillus Calmette–Guerin (BCG), a live attenuated Mycobacterium bovis strain is considered a promising candidate as a vector system for delivery of foreign antigens to the immune system. The gene coding for the Leptospira interrogans external membrane protein ...

Journal of Equine Veterinary Science, 2011

During a routine trip to a horse slaughterhouse, we found bilateral ovarian teratoma. Macroscopic... more During a routine trip to a horse slaughterhouse, we found bilateral ovarian teratoma. Macroscopic findings were confirmed by the presence of hair, bones, and cartilage. Under microscopy, these tumors had mature foreign tissues as stratified squamous and ...

European Journal of Internal Medicine, 2011

BACKGROUND Tuberculosis is an infectious disease mainly caused by Mycobacterium tuberculosis that... more BACKGROUND Tuberculosis is an infectious disease mainly caused by Mycobacterium tuberculosis that health systems have been battled over time. Nowadays, it is still a big burden among various countries. The most affected are the immunosuppressed, the urban ...

European Journal of Internal Medicine, 2011

European Journal of Internal Medicine, 2010

European Journal of Internal Medicine, 2010

Background: Upper gastrointestinal bleeding is the severe complication of stress-related mucosal ... more Background: Upper gastrointestinal bleeding is the severe complication of stress-related mucosal disease in hospitalized patients. In intensive care units (ICU), risk factors are well defined and only mechanical ventilation and coagulopathy proved to be relevant for significant bleeding. On the contrary, in non-ICU settings there is no consensus about this issue. Nevertheless, omeprazole is still widely used in prophylaxis of bleeding. The objective of our study was to evaluate the relevance of stress-related mucosal disease bleeding in patients admitted to an internal medicine ward, and the role of omeprazole in its prophylaxis. Methods: We conducted a retrospective study in which we analysed consecutive patients who were admitted to our ward over a year. We recorded demographic characteristics of the patients, potential risk factors for stress-related mucosal disease (clinical data, laboratory, and medication), administration of prophylactic omeprazole, and total cost of this prophylaxis. Patients with active gastrointestinal bleeding on the admission were excluded. We recorded every upper gastrointestinal bleeding event with clinical relevance. Results: Five hundred and thirty-five patients, mean age 70 years, mean length of stay 9.6 ± 7.7 days; 140 (26.2%) patients were treated with 40 mg of omeprazole intravenously, 193 (36.1%) with 20 mg of omeprazole orally, and 202 (37.8%) patients had no prophylaxis. There was only one episode (0.2%) of clinically relevant bleeding. Conclusion: In patients admitted to an internal medicine ward, incidence of upper gastrointestinal bleeding as a complication of stress-related mucosal disease is low. We found that there is no advantage in prophylaxis with omeprazole.

Clinical and Vaccine Immunology, 2013

The leptospiral immunoglobulin-like (Lig) proteins LigA and LigB possess immunoglobulin-like doma... more The leptospiral immunoglobulin-like (Lig) proteins LigA and LigB possess immunoglobulin-like domains with 90-amino-acid repeats and are adhesion molecules involved in pathogenicity. They are conserved in pathogenic Leptospira spp. and thus are of interest for use as serodiagnostic antigens and in recombinant vaccine formulations. The N-terminal amino acid sequences of the LigA and LigB proteins are identical, but the C-terminal sequences vary. In this study, we evaluated the protective potential of five truncated forms of LigA and LigB proteins from Leptospira interrogans serovar Canicola as DNA vaccines using the pTARGET mammalian expression vector. Hamsters immunized with the DNA vaccines were subjected to a heterologous challenge with L. interrogans serovar Copenhageni strain Spool via the intraperitoneal route. Immunization with a DNA vaccine encoding LigBrep resulted in the survival of 5/8 (62.5%) hamsters against lethal infection (P < 0.05). None of the control hamsters or animals immunized with the other vaccine preparations survived. The vaccine induced an IgG antibody response and, additionally, conferred sterilizing immunity in 80% of the surviving animals. Our results indicate that the LigBrep DNA vaccine is a promising candidate for inclusion in a protective leptospiral vaccine.