Larval immunity in mosquitoes

The National Institute of Allergy and Infectious Diseases, operating under the Department of Health and Human Services, awarded Kansas State University $238,247 on September 1, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to conduct research on larval immunity in the African malaria mosquito Anopheles gambiae.

The project identifies molecular interactions that regulate melanization through proteolytic activation of phenoloxidase in An. gambiae larvae, with the long-term goal of defining proteolytic systems that regulate mosquito immunity to predict and manipulate vector-pathogen interactions for malaria prevention. The research pursues three specific aims: determining the roles of newly identified CSP and CSPHS proteins in the melanization network, identifying the molecular environments of these proteins, and building the molecular interaction network that defines melanization. Understanding the protease network controlling melanization in An. gambiae contributes to predicting mosquito fitness outcomes and monitoring efficacy of novel vector control strategies employing microbial agents.

Performance occurs in Kansas through August 31, 2028. This project grant supports fundamental research on mosquito physiology to inform vector population control schemes utilizing gene drive, male sterility, Wolbachia-based methods, and fungal biocontrol agents.

Abstract

The african malaria mosquito, anopheles gambiae, is one of the major vectors of life-threatening human malaria parasites. Vector population control remains the most common and effective malaria prevention tool. Novel vector population control schemes, utilizing gene drive, male sterility, wolbachia-based methods, and fungal biocontrol agents in part rely on detailed molecular understanding of mosquito physiology. For this reason, mosquito innate immunity has received much attention, as IT is a major determinant of vector competence and fitness of mosquitoes. Humoral innate immune responses, including those in mosquitoes are regulated in part by protease cascades, whose dysregulation reduces vectorial capacity by shortening adult female life span and biting frequency. The long-term goal of this project is to define the proteolytic systems that regulate mosquito immunity to predict and manipulate vector-pathogen interactions to prevent disease. The objective of this project is to identify the molecular interactions that regulate melanization through the proteolytic activation of a key enzyme called phenoloxidase (PO) in an. Gambiae for the following rationale: the protease network that controls melanization in an. Gambiae contributes significantly to mosquito fitness, as its dysregulation affects longevity, biting frequency, ability to resist and/or survive bacterial, fungal, and malaria parasite infections. Thus, deep understanding of its molecular make-up could be employed to monitor long-term efficacy of novel vector control strategies that employ microbial agents and manipulate infection outcome. Guided by extensive published and unpublished preliminary results, this project will pursue the following three aims: (1) determine the roles of newly identified CSP & csphs in the melanization network; (2) identify the molecular environments of CSP and csphs; and (3) build the molecular interaction network that defines melanization in mosquito adults. The first aim will test the hypothesis that the CSP-csph network regulates melanization by positive and negative feedback loops that are critical for resistance to opportunistic pathogens encountered by mosquitoes. The second aim will test the hypothesis that the assembly of the melanization network on microbial surfaces relies on sets of prrs. The third aim will test the hypothesis that combining distinct network data not only predicts key proteins in the melanization response but also their specific molecular interactions. The proposed research is innovative, as IT evaluates protease cascades as a single, integrated network that controls mosquito humoral immunity and pushes forward novel transdisciplinary approaches to mosquito immunity. This project is significant, as IT will provide a comprehensive understanding of mosquito immune system regulation, including its key players and their interactions that may then be genetically or chemically manipulated to reduce malaria parasite transmission and enhance the efficacy of biological control strategies targeting an. Gambiae.