ABSTRACT
It is documented that people living in malaria endemic areas acquire immunity against malaria after repeated infections. Studies involving passive transfer of IgG from immune adults to the nonimmune subjects have shown that circulating antibodies play an important role, and that immune adults possess protective antibodies, which susceptible malaria patients do not. Through a differential immunoscreen, we have identified several novel cDNA clones, which react exclusively and yet extensively with immune sera samples. Specific antisera raised against the immunoclones inhibit the growth of parasites in culture. The clones studied so far turn out to be novel conserved Plasmodium genes. In order to study the response of sera of adults from malaria endemic areas of India and Africa to these immunogens, we carried out ELISA assays using these immunopeptides, other P. falciparum specific antigens, peptides, antigens from other infections such as mycobacterial infections and other proteins such as BSA. Children from the same areas and normal healthy urban people showed very little activity to each of these categories. A large percentage of adults from endemic areas responded positively to all the malarial immunogens tested. However, the same persons also showed high response to other antigens and proteins as well. The implications of these results are reported in this paper.
Subject(s)
Adolescent , Adult , Amino Acid Sequence , Animals , Antibodies, Protozoan/blood , Antigens, Protozoan/genetics , Child , Endemic Diseases , Enzyme-Linked Immunosorbent Assay , Humans , India/epidemiology , Kenya/epidemiology , Malaria, Falciparum/blood , Membrane Proteins/genetics , Molecular Sequence Data , Peptide Fragments/immunology , Plasmodium falciparum/immunology , Protozoan Proteins/geneticsABSTRACT
Immunological adjuvants (alum, liposomes and saponin) were utilized to stimulate cell-mediated immune response in Plasmodium berghei infected Balb/c mice. It was shown that malaria antigen mixed with adjuvant induced appreciably delayed type hypersensitivity and production of migration inhibition factor compared to antigen alone.
Subject(s)
Adjuvants, Immunologic , Animals , Antigens, Protozoan/immunology , Cell Migration Inhibition , Female , Hypersensitivity, Delayed , Macrophage Migration-Inhibitory Factors/analysis , Malaria/immunology , Male , Mice , Mice, Inbred BALB C , Plasmodium berghei/immunologyABSTRACT
The circulating immune complexes have been detected in the sera of albino rats infected with Plasmodium berghei and rhesus monkeys infected with P. knowlesi by (i) quantitative cryoprecipitation assay and (ii) polyethylene glycol assay. In the rodent model, the levels of circulating immune complexes increased during infection and decreased considerably in the post-infection period. In the simian system, high levels were detected during peak parasitaemia. Polyethylene glycol precipitate obtained from the sera during acute P. knowlesi infection when analysed by Immunoelectrophoresis was found to contain (i) monkey IgG, (ii) four other components of monkey plasma, (iii) two components of normal monkey erythrocytes and (iv) antigen(s) of P. knowlesi.