Serodiagnostic and immunoprophylactic potential of a 78kDa protein of Leishmania donovani of Indian origin.
BACKGROUND
The serodiagnosis of visceral leishmaniasis due to Leishmania donovani using crude parasite antigen is complicated in many endemic areas by cross-reactions with serum from humans infected with other protozoan diseases. The search for pure antigens avoiding such cross-reactions is in progress. Developing a vaccine against cutaneous leishmaniasis has been much more successful than against visceral leishmaniasis. Immunoprophylactic studies using various combinations of antigens and adjuvants are also in progress, and several strategies are in use, with varying degrees of success.


METHODS
Promastigotes of Leishmania donovani were used. The 78kDa protein was purified by a monoclonal antibody tagged CNBr sepharose CL-4B column. The presence of the protein in both stages of the parasite and in kala-azar patient serum was analyzed by western blotting. ELISA was used for serodiagnosis and isotype analysis of antibodies produced in immunized mice. Immunoprophylactic studies were carried out based on in vitro transformation of amastigotes to promastigotes.


RESULTS
The 78 kDa membrane protein, present in both amastigote and promastigote forms of the parasite, was purified to homogeneity. The protein was found to have serodiagnostic potential to detect kala-azar. BALB/c mice immunized with 78kDa protein revealed reduction in spleen parasitemia. Isotype profiles of antibodies produced by immunized mice showed increased production of IgG2a and decreased IgG1 levels.


CONCLUSIONS
Our results demonstrated, for the first time, the serodiagnostic and immunoprophylactic use of a pure membrane protein isolated from Leishmania donovani of Indian origin.
Mukherjee
Mandira
M
Leishmania Division, Indian Institute of Chemical Biology, Calcutta, India. mandir_71@yahoo.com
Bhattacharyya
Anindita
A
Duttagupta
Swadesh
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007132:Immunoglobulin Isotypes / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D007194:India; D007893:Leishmania donovani / Q000254:growth & development / Q000276:immunology* / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000097:blood / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control*; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D018512:Parasitemia / Q000517:prevention & control; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D016052:Protozoan Vaccines / Q000276:immunology* / Q000302:isolation & purification; D014611:Vaccination
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D008565:Membrane Proteins; D015800:Protozoan Proteins; D016052:Protozoan Vaccines