# Antibody response induced by structural proteins from Triatoma virus as potential adjuvants in experimental immunisation models

## TL;DR

This study explores how proteins from Triatoma virus can boost immune responses in vaccines for leishmaniasis and Chagas disease.

## Contribution

The study demonstrates the adjuvant potential of Triatoma virus structural proteins in modulating specific antibody responses.

## Key findings

- VP structural proteins induced IgG2b and IgG3 antibodies in Leishmania amazonensis immunization.
- VPs elicited IgG2b with balanced IgG2a and IgG3 in Trypanosoma cruzi models.
- VPs showed lower IgG1 responses compared to other adjuvants.

## Abstract

Virus-Like Particles (VLPs) are viral protein structures widely used as adjuvants in vaccine formulations due to their ability to stimulate the innate immune response, thereby contributing to the activation of adaptive immunity through the production of different IgG subclasses. The present study evaluated the adjuvant potential of recombinant structural proteins of the Triatoma virus VLPs (TrV-VLPs: VP1, VP2, and VP3) in experimental immunisation protocols for American Cutaneous Leishmaniasis and Chagas disease.

BALB/c mice were immunised with native antigens of Leishmania amazonensis or chimeric recombinant antigens of Trypanosoma cruzi in association with different adjuvants, including aluminium hydroxide, incomplete Freund’s adjuvant, and VPs structural proteins. The induction of specific antibodies (anti-L. amazonensis or anti-recombinant proteins of T. cruzi) was measured by ELISA to determine the IgG subclass profile.

Immunisation with L. amazonensis antigens revealed that VPs preferentially induced IgG2b and IgG3 antibodies, whereas in experiments with T. cruzi antigens, IgG2b was predominant, accompanied by similar levels of IgG2a and IgG3, compared to lower IgG1 responses. These findings suggest that recombinant structural proteins of TrV-VLPs represent a promising adjuvant strategy capable of modulating humoral immune responses, offering potential applications in vaccine development against protozoan parasites such as Leishmania spp. and T. cruzi.