In order to understand the regulatory role of cytokines on the antibody response in loiasis, BALB/c mice deficient in IL-4 and IL-5 cytokine genes were infected with human Loa loa and the animals were dissected at different time interval to assess the survival of worms. The IgG1, IgG2, IgG3 and IgE responses to Loa loa adult worm and L3 total extract antigens were measured at different time points of infection by ELISA. Worms were recovered up to 360 days post infection. The recovery rate decreased significantly with the time of infection. Worms recovered after 120 days were from the heart.
In the absence of IL-4 and IL-5 which are key cytokines that stimulate B cell proliferation and antibody production, the host mounted an immune response that was predominantly IgG1, IgG2, IgG3. These antibody responses increased significantly (≤ 0.001) with the time of infection. IgE showed little variation with the time of infection.
The high IgG1, IgG2, IgG3 response observed in these mice deficient in IL-4 and IL-5 suggest a bypass mechanism used by these animals to stimulate antibody response that accounted for the killing of the worms. It is probably that worms found in the heart escaped these responses. This model presents some avenues for further dissection of the host immune response to filarial infections.
- 02 Feb 2015
- Dr. Nicholas Tendongfor