Purified PTP1 protein induces antigen-specific protective immunity against Encephalitozoon cuniculi

Abstract

Microsporidiosis poses a problem for immunocompromised individuals including patients with HIV infection as well as those with organ transplantation. Recent reports from Africa have suggested that microsporidiosis with diarrhea is an independent risk factor for malnutrition in children. Previous studies from our laboratory have demonstrated that CD8 + T cells are an essential component of protective immunity against the microsporidium Encephalitozoon cuniculi. Mutant mice lacking this T cell subset or cytotoxic function are unable to clear the infection and ultimately succumb to the disease. However, information regarding the antigens involved in the elicitation of CD8 + T cell response is not available. In this study, we report that immunization of animals with Encephalitozoon hellem polar tube protein 1 (rEhPTP1) induces a strong T cell response in vaccinated animals. Splenic dendritic cells pulsed with rEhPTP1 are able to induce E. cuniculi specific CD8 + T cell response with no effect on the CD4 + T cell subset. This is the first report identifying a protein capable of inducing CD8 + T cell immunity, which is conserved in other microsporidial species of human importance.

Gastrointestinal Cell Mediated Immunity and the Microsporidia

“…An additional problem with microsporidia is lack of information about CD8 + T cell epitopes, which makes it impossible to generate tetramers without which bona fide antigen-specific cells cannot be identified. However, this situation has shown some progress as the major polar tube protein (PTP1) has been reported to induce a significant antigen-specific systemic CD8 + T cell response [30] and potential epitopes have been identified. Attempts to generate tetramers based on this information are underway and efforts need to be put into identifying other antigens involved in the generation of this response.…”