Safety and skin delayed-type hypersensitivity response in vervet monkeys immunized with Leishmania donovani sonicate antigen delivered with adjuvants / Segurança e reação de hipersensibilidade tardia na pele de macacos vervet imunizados com antígeno sonicado de Leishmania donovani junto com adjuvantes

In this study, we report on the safety and skin delayed-type hypersensitivity (DTH), responses of the Leishmania donovani whole cell sonicate antigen delivered in conjunction with alum-BCG (AlBCG), Montanide ISA 720 (MISA) or Monophosphoryl lipid A (MPLA) in groups of vervet monkeys. Following three intradermal injections of the inoculums on days 0, 28 and 42, safety and DTH responses were assessed. Preliminary tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) levels were also measured and these were compared with DTH. Only those animals immunized with alum-BCG reacted adversely to the inoculum by producing ulcerative erythematous skin indurations. Non-parametric analysis of variance followed by a post-test showed significantly higher DTH responses in the MISA+Ag group compared with other immunized groups (p < 0.001). The MPLA+Ag group indicated significantly lower DTH responses to the sonicate antigen compared with the AlBCG+Ag group. There was a significant correlation between the DTH and cytokine responses (p < 0.0001). Based on this study we conclude that Leishmania donovani sonicate antigen containing MISA 720 is safe and is associated with a strong DTH reaction following immunization.

Neste estudo reportamos segurança e resposta de hipersensibilidade tardia (DTH) do antígeno sonicado de células totais de Leishmania donovani introduzidos juntamente com alume-BCG (AIBCG) Montanide ISA 720 (MISA) ou lípide A monofosforilado (MPLA) em grupos de macacos vervet. Depois de três injeções intradérmicas do inóculo nos dias 0, 28 e 42 segurança e resposta DTH foram avaliados. Preliminarmente níveis de fator de necrose tumoral alfa (TNF-α) e interferon gama (IFN-γ) foram também medidos e comparados com o DTH. Somente os animais imunizados com alume-BCG reagiram de maneira diversa ao inóculo produzindo indurações ulceradas e eritematosas na pele. Análise não paramétrica de variação seguida por um teste posterior mostraram resposta significantemente mais alta do DTH no grupo MISA + Ag quando comparado com outros grupos imunizados (p < 0.001). O grupo MPLA + Ag demonstrou resposta DTH significantemente menor do antígeno sonicado comparado com o grupo AIBCG + Ag. Houve correlação significante entre o DTH e a resposta às citocinas (p < 0.0001). Baseados neste estudo concluímos que o antígeno sonicado de Leishmania donovani contendo MISA 720 é seguro e está associado com forte reação DTH após imunização.

Immunological correlates of cure in the first American Cutaneous Leishmaniasis patient treated by immunotherapy in Argentina: A case report. / Correlatos inmunológicos de curación en el primer paciente con Leishmaniasis Cutánea Americana tratado con inmunoterapia en Argentina: Reporte de un caso

A patient with localized cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis infection was treated with an antigen containing heat-killed L. (L.) amazonensis promastigotes plus BCG. Expression of T-cell differentiation, memory and senescence receptors markers were analyzed on T cell subpopulations, in order to establish the correlation between the percentages of expression of these receptors and his clinical status, at different stages of his follow up. The following case reports on the achievement of a successful clinical outcome with complete resolution after receiving immunotherapy. A thorough clinical and immunological follow up supporting the healing process of this patient’s lesion is presented in detail.

Un paciente con leishmaniasis cutánea localizada producida por Leishmania (Leishmania) amazonensis fue tratado con un antígeno compuesto por promastigotes de L. (L.) amazonensis muertos por calor combinado con BCG. Se analizó la expresión de distintos receptores de diferenciación, de memoria y de senescencia en las subpoblaciones de células T, con el fin de establecer una relación entre los porcentajes de expresión de dichos receptores y la clínica del paciente en diferentes momentos del seguimiento. Se reporta en este caso un resultado exitoso, con resolución completa de la lesión después de recibir la inmunoterapia, y se presenta en detalle un seguimiento clínico e inmunológico completo durante el proceso de curación.

CD8+ T-cell Activation in Mice Injected with a Plasmid DNA Vaccine Encoding AMA-1 of the Reemerging Korean Plasmodium vivax

Relatively little has been studied on the AMA-1 vaccine against Plasmodium vivax and on the plasmid DNA vaccine encoding P. vivax AMA-1 (PvAMA-1). In the present study, a plasmid DNA vaccine encoding AMA-1 of the reemerging Korean P. vivax has been constructed and a preliminary study was done on its cellular immunogenicity to recipient BALB/c mice. The PvAMA-1 gene was cloned and expressed in the plasmid vector UBpcAMA-1, and a protein band of approximately 56.8 kDa was obtained from the transfected COS7 cells. BALB/c mice were immunized intramuscularly or using a gene gun 4 times with the vaccine, and the proportions of splenic T-cell subsets were examined by fluorocytometry at week 2 after the last injection. The spleen cells from intramuscularly injected mice revealed no significant changes in the proportions of CD8+ T-cells and CD4+ T-cells. However, in mice immunized using a gene gun, significantly higher (P<0.05) proportions of CD8+ cells were observed compared to UB vector-injected control mice. The results indicated that cellular immunogenicity of the plasmid DNA vaccine encoding AMA-1 of the reemerging Korean P. vivax was weak when it was injected intramuscularly; however, a promising effect was observed using the gene gun injection technique.

Vertical toxoplasmosis in a murine model. Protection after immunization with antigens of Toxoplasma gondii incorporated into liposomes

Distinct Toxoplasma gondii antigens were entrapped within liposomes and evaluated for their ability to protect Balb/c mice against congenital transmission: soluble tachyzoite antigen (L/STAg), soluble tissue cyst antigen (L/SCAg), soluble tachyzoite plus tissue cyst (L/STCAg) or purified 32kDa antigen of tachyzoite (L/pTAg). Soluble tachyzoite antigen alone in PBS (STAg) or emulsified in Freund's Complete Adjuvant (FCA/STAg) was also evaluated. Dams were inoculated subcutaneously with these antigens 6, 4 and 2 weeks prior to a challenge with four tissue cysts of the P strain of T. gondii orally between 10 and 14 days of pregnancy. Significant diminution differences were observed between the frequency of infected pups born of the dams immunized with the antigens incorporated into liposomes and that of pups born of the dams immunized with antigen emulsified in FCA or non immunized group (p<0.05). There was a significant decrease in the number of pups born dead in the groups L/STAg, L/SCAg and L/pTAg when compared with pups from all other groups (p <0.05). All dams immunized with or without adjuvant showed an antibody response and a proliferation of T-cells. However, no correlation was found between immune response and protection against the challenge

Protection against Toxoplasmosis in Mice Immunized with Different Antigens of Toxoplasma gondii Incorporated into Liposomes

Different toxoplasma antigens were entrapped within liposomes and evaluated, in this form, for their ability to protect Swiss mice against toxoplasma infection: soluble tachyzoite antigen (L/TAg), tissue cyst (L/CAg), tachyzoite plus tissue cyst (L/TCAg) or purified antigen of tachyzoite (L/pTAg). The protein used in L/pTAg was purified from tachyzoites using a stage-specific monoclonal antibody which reacted at a molecular weight of 32 kD in SDS PAGE and silver stain using reduced condition. To compare the immuno-adjuvant action of liposomes and of Freund's Complete Adjuvant (FCA), another group of mice was immunized with soluble tachyzoite antigen (STAg) emulsified in FCA (FCA/TAg). Control groups were inoculated with (STAg) alone, phosphate-buffered saline (PBS), FCA with PBS (FCA/PBS) and empty liposomes (L/PBS). Mice were inoculated subcutaneously with these antigens six, four and two weeks before a challenge with 80 tissue cysts of the P strain of Toxoplasma gondii orally. All mice immunized with or without adjuvant showed a humoral response, as measured by Elisa. However, no correlation was found between antibody titer and protection against the challenge. All mice immunized with L/pTAg or L/TCAg survived (100), whereas 80 percent and 90 percent of mice from groups which received respectively PBS or FCA/PBS and L/PBS died. All mice immunized with antigens entrapped within liposomes (L/TAg, L/CAg, L/TCAg and L/pTAg) showed low numbers of intracerebral cysts

A dhfr-ts- Leishmania major Knockout Mutant Cross-protects against Leishmania amazonensis

E10-5A3 is a dhfr-ts- Leishmania major double knockout auxotrophic shown previously to induce substantial protection against virulent L. major infection in both genetically susceptible and resistant mice. We investigated the capacity of dhfr-ts- to protect against heterologous infection by L. amazonensis. The degree of protection was evaluated by immunization of BALB/c or C57BL/6 mice with E10-5A3, followed by L. amazonensis challenge. Whether immunized by subcutaneous (SC) or intravenous (IV) inoculation, susceptible and resistant mice displayed a partial degree of protection against challenge with virulent L. amazonensis. SC-immunized BALB/c mice developed lesions 40 to 65 percent smaller than non immunized mice, while IV immunization led to protection ranging from 40 to 75 percent in four out of six experiments compared to non immunized animals. The resistant C57BL/6 mice displayed comparable degrees of protection, 57 percent by SC and 49 percent by IV immunization. Results are encouraging as it has been previously difficult to obtain protection by SC vaccination against Leishmania, the preferred route for human immunization

An outbreak of human Leishmania (Viannia) braziliensis infection

The occurence of acute cutaneous leishmaniasis among inhabitants of 10 farms within 10 Km of the hamlet of Corte de Pedra, Bahia, Brazil was studied prospectively from 1984-l989. A mean population of 1,056 inhabitants living in 146 hourses were visited every 6 months and the numberof sKin ulcers recorded. A leishmanin skin test survey was done people with suggestive skin scars or active disease in l984. The incidence of skin ulcers due to Leishmania (Viannia) brasiliensis (Vlb) reached 83/1,000 inhabitants but declined sharply in the subsequent 2 years. Retrospective data shows that leishamiasis is a sporadic endemic disease. Although the reasons for this epidemic are unclear some possible aetiological factors are discussed