In immunocompromised people, infection with the opportunistic fungal fungus Pneumocystis jirovecii causes life-threatening pneumonia. Individuals at risk of Pneumocystis infection, in addition to HIV-1 infected people, include those undergoing immunosuppressive treatments as a result of transplantation, cancer, or autoimmune illness. Antibiotic therapy is not always effective, and it does not prevent obstructive lung disease once the infection has been eradicated. As a result, it is critical to create more effective anti-PCP treatment options. In a non-human primate model of HIV-induced immunosuppression, researchers found that the Pneumocystis recombinant protein KEX1 promotes protective immunity against the development of PCP. The immunogenicity of KEX1 vaccination in healthy rhesus macaques, as well as the persistence of these responses during drug-induced immunosuppression with tacrolimus (FK506) and methylprednisolone, were investigated in this work. They discovered that KEX1 vaccination before the initiation of the immunosuppressive regimen resulted in a robust and long-lasting antibody response that lasted throughout the immunosuppressive therapy.

Furthermore, boosting with KEX1 during immunosuppression resulted in the recollection of memory responses to recombinant KEX1. The persistence of the anti-KEX1 reaction and the capacity to elicit a memory response during immunosuppressive medication offer proof-of-concept data that supports future research of KEX1 as a preventive vaccination to prevent PCP in drug-induced immunosuppression. This method provides important insights for the development of therapeutic and prophylactic PCP options in patients receiving severe immunosuppressive treatment.