Immunity in Filarial Infections: Lessons from Animal Models and Human Studies

Our understanding of immunity to filarial infection is enigmatic and continues to be passionately debated. The mechanisms whereby filarial nematodes are killed in vivo and how these parasites avoid these mechanisms are poorly understood. Although vaccination studies in permissive animals took off seven decades ago, the exact mechanisms driving protective immunity are extensively being investigated. Currently, little is known regarding the collective functions or counter-regulatory mechanisms of the antibody isotypes in filarial infection with respect to protective immunity. Establishing the functional role of antibody isotypes and cytokines in the various infection phenotypes can contribute immensely to current knowledge in filarial immunology. This paper reviews insight into protective immunity in filarial infection with focus on humoral and cellular responses from animal models and human studies.