Avaliação in vivo do uso de anticorpos IgY como moléculas para proteção e tratamento contra doenças diarreicas

Abstract

Enteric infections are a major cause of morbidity and mortality, especially in developing countries, primarily affecting children under five years of age, the elderly, pregnant women, and immunocompromised individuals. Furthermore, the increasing bacterial resistance to antimicrobials has driven the search for alternative strategies for the prevention and treatment of these infections. In this context, immunoglobulin Y (IgY) stands out as a promising alternative for passive immunotherapy due to its high specificity, ease of acquisition, lower production cost, and ethical advantages compared to antibodies produced in mammals. This dissertation aimed to gather evidence on the applications of IgY technology and evaluate the potential of previously produced IgY antibodies against synthetic peptides derived from enteropathogens. Chapter I of this dissertation presents a literature review on the main diagnostic and therapeutic applications of these antibodies. Chapter II, the recognition capacity of the antibodies against the bacteria Shigella flexneri and Salmonella spp. was evaluated. This study investigated the identification of diarrheagenic Escherichia coli subtypes by flow cytometry, as well as their in vitro activity through agar diffusion assays, minimum inhibitory concentration, and bacterial growth monitoring. Subsequently, the protective potential of antibodies was investigated in a murine model of Shigella flexneri infection. The results demonstrated a high capacity for recognition of enteropathogens by anti-P1 and anti-P8 antibodies, although no bacteriostatic or bactericidal activity was observed under the experimental conditions evaluated. In the in vivo model, treatment with the anti-P1 antibody showed a trend towards clinical protection against infection. These findings reinforce the potential of IgY technology as a complementary strategy for the control of enteropathogens and encourage the development of new passive immunotherapy approaches against diarrheal diseases. KEYWORDS: Shigella; Escherichia coli; diarrheagenic; Immunoglobulin Y.