Basic immunological toolbox for genus peromsycus, infection tolerant reservoirs of zoonotic agents

The National Institute of Allergy and Infectious Diseases (NIAID) awarded $431,750 to the University of California, Irvine under the Allergy and Infectious Diseases Research program (CFDA 93.855) for a two-year developmental project commencing July 1, 2025 and concluding June 30, 2027. This Project Grant supports the development of a basic immunological toolbox for the genus Peromyscus, specifically targeting white-footed deermice (Peromyscus leucopus) and related species that serve as natural reservoirs for zoonotic agents including Lyme disease, anaplasmosis, babesiosis, and hantavirus.

The primary deliverables include the creation of monoclonal antibodies for leukocyte phenotyping suitable for flow cytometry and cell sorting applications, and the characterization of immunoglobulin G (IgG) subclasses in Peromyscus species. These research outputs will address a significant gap in available immunological reagents and assays, as existing antibodies developed for mice or humans lack sufficient cross-reactivity with deermouse orthologous proteins. By leveraging multiplexed single-cell RNA sequencing (scRNA-seq) and a closed colony of deermice representative of wild populations, the project will generate critical tools to advance in-depth immunological and host response studies essential for vaccine development, genetic modification research, and translational investigations in zoonotic disease management.

Abstract

Peromyscus leucopus, the white-footed deermouse, is a natural host and major reservoir for the agents of lyme disease, anaplasmosis, and babesiosis among other zoonoses in north america. The related species p. Maniculatus is a reservoir for hantavirus as well as lyme disease. While mouse-like in appearance, these deermice are more closely related to hamsters and voles than to MUS or rattus. P. Leucopus also has longevity 2-3 times that of the house mouse and has a more restrained inflammatory response to TLR agonists and infection. While translational interest in p. Leucopus increases, including as a target for field vaccines and for genetic modification and then environmental release, there are very limited tools besides genome-wide and targeted RNA-SEQ for in-depth study of the immunology and host responses of these animals. Examples are reagents and assays for flow cytometry and IGG subclasses. Antibodies for phenotyping white cells that are developed for study of mice or humans seldom have sufficient cross-reactivity with deermouse orthologous proteins to succeed. This application for a 2-year developmental project recognizes this need for the field to advance and proposes to take the first steps to remedy the deficiency. Using our access to a closed colony of p. Leucopus that is representative of wild populations in terms of genetic diversity, we will carry out work on the following specific aims: aim 1. Antibodies for phenotyping leukocytes of peromyscus. First will be a pan-leukocyte monoclonal antibody suitable for flow cytometry and sorting. The isolated leukocytes from different outbred deermice will be subjected to multiplexed scrna-SEQ, the results of which provide either confirmation of provisional choices (i.e. CD14 and CD19) or guidance on alternatives for marker antibodies of narrower specificity. Aim 2. IGG subclasses of peromyscus. Using the deduced amino acid sequences for constant regions of heavy chains, we will characterize and measure subclasses by LC-MS/MS. Discriminating peptides will be used for eliciting sub-class specific antibodies. The affinities of different subclasses for FC receptor ligands, like protein a will be assessed. Aim 3. Application of tools to models of systemic inflammation and of infection. The utility and informativeness of the outcomes of aims 1 and 2 will be assessed in our established p. Leucopus models of infection with b. Burgdorferi or systemic inflammation from TLR agonists.