# Development of a vaccine to prevent Pneumocystis pneumonia

> **NIH NIH R41** · NXT BIOLOGICS, INC. · 2020 · $272,439

## Abstract

Despite the fact that fungal diseases are an increasing clinical burden, particularly among
immunocompromised patients, there are no anti-fungal vaccines approved for clinical use. The fungal
opportunistic pathogen, Pneumocystis jirovecii is the causative agent of Pneumocystis pneumonia (PCP),
which remains a serious AIDS-defining, opportunistic infection and is of increasing concern in persons
receiving immunosuppressive therapies, including organ transplant recipients, cancer patients, individuals with
inflammatory disease and in persons experiencing natural immunosuppression due to aging, congenital or
acquired immunosuppressive states. In addition to causing PCP, several studies have shown an association
between Pc colonization and chronic obstructive pulmonary disease (COPD) in both HIV-infected and non-HIV
infected populations. Each of these patient populations would benefit from either a prophylactic PCP vaccine
administered prior to immunosuppression (for example, prior to a clinical course of immunotherapy) or in
populations at risk for HIV infection or individuals at the time of diagnosis of HIV infection. The overall goal of
this research is to develop a vaccine for prevention of PCP and related pulmonary sequelae in HIV+ and other
immunocompromised populations. Toward this end, we have identified and developed a vaccine candidate
based on the Pneumocystis protein, kexin. We have produced a vaccine candidate based on Pneumocystis
protein, kexin, and showed that immunization of non-human primates (NHP) prior to simian immunodeficiency
virus (SIV) infection induces high level, kexin-specific plasma and lung immunoglobulin titers and protects
against Pneumocystis pneumonia. The objective of this Phase I application is to complete lead optimization of
the vaccine by testing the immunogenicity of the Pneumocystis jirovecii-derived kexin protein derivative. We
will assess the immune response in NHPs following immunization and boost with the P. jiroveciii recombinant
peptide in SIV-infected macaques and will evaluate the duration and quality of the specific memory responses
in the immunosuppressed state. With the completion of this proof of concept study, we will focus efforts on
preparation and evaluation of the vaccine for clinical trial.

## Key facts

- **NIH application ID:** 9906567
- **Project number:** 1R41AI145416-01A1
- **Recipient organization:** NXT BIOLOGICS, INC.
- **Principal Investigator:** MICHAEL Robert DOWNES
- **Activity code:** R41 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $272,439
- **Award type:** 1
- **Project period:** 2020-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9906567

## Citation

> US National Institutes of Health, RePORTER application 9906567, Development of a vaccine to prevent Pneumocystis pneumonia (1R41AI145416-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9906567. Licensed CC0.

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