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Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis.

ABSTRACT: In experimental murine cutaneous leishmaniasis, the purified Leishmania pifanoi amastigote protein P-4 has been shown to induce significant protection against infection. Further, recent studies examining the response of peripheral blood mononuclear cells (PBMC) from Leishmania braziliensis-infected human patients have demonstrated that the P-4 protein selectively elicits a significant TH1-like response. Because a TH1-like response is associated with cure, epitope studies were conducted to further evaluate the human response to P-4. PBMC from confirmed cutaneous leishmaniasis patients infected with L. braziliensis in Rio de Janeiro, Brazil, an area where the disease is endemic, were examined for T-cell proliferation and/or cytokine production in response to whole-parasite homogenate, isolated P-4 protein, and/or P-4 peptides. Twenty of the 22 patients (91%) examined responded to the native P-4 protein by proliferation and/or gamma interferon (IFN-gamma) production. According to the proliferation data, PBMC from 14 patients (64%) were found to respond to the intact P-4 protein (stimulation index of >/=2.5). Fifty-seven percent of the P-4-responsive patients studied responded to at least one of the P-4 peptides; 11 individual peptides were found to elicit a proliferative response. Of 17 patients examined for cytokine production, no PBMC produced detectable interleukin-4 in response to P-4 protein or peptides. However, PBMC from 14 patients (82%) produced significant levels of IFN-gamma (>/=20 pg/ml) in response to native P-4 protein. Nineteen of the 23 peptides were found to elicit an IFN-gamma response from at least two patients. These data indicate that multiple epitopes spanning the entire P-4 molecule are responsible for the TH1-like immune response observed, indicating that the intact P-4 amastigote molecule, rather than selected peptides, may prove to be the most useful for leishmaniasis vaccine development.

SUBMITTER: Haberer JE

PROVIDER: S-EPMC108319 | biostudies-literature | 1998 Jul

REPOSITORIES: biostudies-literature

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Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis.

Haberer J E JE Da-Cruz A M AM Soong L L Oliveira-Neto M P MP Rivas L L McMahon-Pratt D D Coutinho S G SG

Infection and immunity 19980701 7

In experimental murine cutaneous leishmaniasis, the purified Leishmania pifanoi amastigote protein P-4 has been shown to induce significant protection against infection. Further, recent studies examining the response of peripheral blood mononuclear cells (PBMC) from Leishmania braziliensis-infected human patients have demonstrated that the P-4 protein selectively elicits a significant TH1-like response. Because a TH1-like response is associated with cure, epitope studies were conducted to furthe ...[more]

PMID: 9632572

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Project description:Wild canids and domestic dogs are the main reservoir of zoonotic visceral leishmaniasis (VL) caused by Leishmania infantum (syn.: Leishmania chagasi). Serological diagnosis of VL is therefore important in both human and dog leishmaniasis from a clinical and epidemiological point of view. Routine diagnosis of VL is traditionally carried out by immunofluorescent antibody test (IFAT), which is laborious and difficult to standardize and to interpret. In the last decade, however, several specific antigens of Leishmania infantum have been characterized, allowing the development of a recombinant-based immunoassay. Among them, the whole open reading frame encoding K9 antigen, the gene fragment encoding the repetitive sequence of K26, and the 3'-terminal gene fragment of the kinesin-related protein (K39sub) were previously evaluated as diagnostic markers for canine leishmaniasis and proved to be independent in their antibody reactivity. Since sensitivity of serological test is usually higher in multiple-epitope format, in this study the relevant epitopes of K9, K26, and K39 antigens were joined by PCR strategy to produce the chimeric recombinant protein. The resulting mosaic antigen was found highly expressed in Escherichia coli and efficiently purified by affinity chromatography. Antigenic properties of this recombinant antigen were evaluated by indirect enzyme-linked immunosorbent assay (ELISA) using a panel of human and dog sera previously characterized by parasitological and/or serological techniques. Chimeric ELISA showed 99% specificity in both human (n = 180) and canine (n = 343) control groups, while sensitivity was higher in canine VL (96%, n = 213) than in human VL (82%, n = 185). Accordingly, concordance between IFAT and canine chimeric ELISA (k = 0.95, 95% confidence interval = 0.93 to 0.98) was higher than between IFAT and human chimeric ELISA (k = 0.81, 95% confidence interval = 0.76 to 0.87). Results suggest the potential use of this new antigen for routine serodiagnosis of VL in both human and canine hosts.

Dataset Information

Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis.

Publications

Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis.

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