Repeated exposure to 31 kDa protein fraction from the salivary gland of Aedes aegypti modulate humoral and cellular immune response in mouse model

Aedes (Ae) aegypti is the primary mosquito vector responsible for transmitting the pathogens that cause Dengue fever and Dengue hemorrhagic fever. We have previously identified 31 kDa and 56 kDa immunogenic proteins from the salivary glands of Ae. aegypti. The 31 kDa fraction primarily contains D7 protein, which has immunomodulatory properties that influence the host's immune response. This study aims to analyze the humoral (IgG) and specific immune responses (represented by IFN-γ and IL-4 cytokines) in a mouse model (Mus musculus) after exposure to the 31 kDa immunogenic protein from the salivary glands of Ae. aegypti. The mice were divided into three treatment groups: group A (elution buffer control), group B (adjuvant control), and group C (31 kDa 0.2 µg/µL + adjuvant). Injections were administered bi-weekly over six weeks. IgG levels and cytokine (IFN-γ and IL-4) concentrations were analyzed using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results showed that repeated exposure to the 31 kDa immunogenic protein elevated the humoral immune response (IgG) and modulated the host's immune response from the Th1 subset to the Th2 subset, characterized by a decrease in IFN-γ and an increase in IL-4 cytokine concentrations. This modulation is important in developing the host immune response against the transmitted dengue pathogen. This finding confirms that the 31 kDa protein is both immunogenic and immunomodulatory, inducing and modulating the immune response in mice. This study recognizes the 31 kDa protein from the salivary gland of Ae. aegypti as a potential target for the development of a vector-based dengue transmission-blocking vaccine.