Jean Paul Akue Mezegue
Centre International de Recherche Médicale De Franceville (CIRMF), Gabon
Title: Immunological and molecular similarities between human filarial Loa loa and Brugia pahangi antigens
Biography
Biography: Jean Paul Akue Mezegue
Abstract
After long-term, 7-year follow-up, Loa loa-exposed individuals from one village in Gabon were divided into four groups according to parasitological and clinical findings, mainly: endemic controls, amicrofilaraemic, low microfilaraemic and high microfilaraemic individuals. This study carried out using Brugia pahangi adults, microfilariae and L3 antigens compared the level of specific isotypes (IgA, IgE, IgG and IgM) and IgG subclasses in different defined groups of villagers. The study showed that the levels of IgG1 and IgM were significantly higher in amicrofilaraemics compared too high and low microfilaraemics. IgG4 was high in all groups, but there was no significant increase in IgG2 and IgG3. Interestingly, the level of IgG1 was inversely correlated with microfilarial density when using L3 antigen (Spearman’s r= –0.839; p<0.0001). Identification of antigen targets of this response shows several molecules with their molecular weight varying from 8 kDa to 150 kDa. Amplification followed by Southern blot of Loa loa DNA using primers designed from Brugia gp29 confirms the homology between B. pahangi and L. loa genes. The removal of the glycosylated portion of the antigen in the B. pahangi adult did not inhibit the reactivity of the major reacting antibodies IgG1 and IgG4 from the L. loa-infected population, suggesting that the reactivity is linked to the peptide backbone. This study shows that the map of the distribution of lymphatic filarial in L. loa endemic zones should be re-evaluated. The similarities in structural epitopes could be exploited in view of a vaccine strategy designed to control L. loa.