Avaliação da resposta imunológica após vacinação ou infecção por Neisseria meningitidis

• Autor(a) principal: Cruz, Aline da Costa
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14356
• topic: Immunological memory; Neisseria meningitidis; HIV; Bactericidal antibody; Opsonizing antibody; Vaccine; Memória imunológica; Neisseria meningitidis; HIV; Anticorpo bactericida; Anticorpo opsonizante; Vacina; Neisseria meningitidis; Meningite; Vacinas meningocócicas; Infecções por HIV; HIV (Vírus); CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Meningococcal disease (MD) is still a serious public health problem and is associated with high morbidity and mortality rates worldwide. MD evokes persistent immune protection against disease in people with normal immune systems. In contrast, protection induced by meningococcal always requires booster injections of the vaccine. In Brazil, Neisseria meningitidis serogroup C (MenC) and B (MenB) have been the main causes of MD for the past years. Currently, there is no universal vaccine against serogroup B. HIV infection has been implicated as a risk factor for the mortality of meningococcal disease. One of the cornerstones of HIV treatment is the use of vaccines for immunopreventable diseases. The anti-MenC conjugated vaccine is often recommended for children and adolescents infected with HIV in Brazil and many other countries. Few studies have addressed the mechanisms by which meningococcal vaccines generate and sustain immunological memory. The aims of this study were: 1) to evaluate the response of bactericidal antibody and memory CD4 T lymphocyte against meningococcus after infection; 2) to evaluate the bactericidal antibody response and memory T cells and memory B cells against meningococcal booster after the Cuban vaccine VA-MENGOC-BC® in volunteers immunized for about 17 years; 3) to investigate the functional antibody response (bactericidal and opsonizing) after immunization with anti-MenC conjugated vaccine (CRM197) in individuals infected with HIV. After infection, 83% of patients diagnosed as having DM by latex and/or culture test, had protective titers of bactericidal antibodies, but there was no association between the titers of bactericidal antibodies and the total specific immunoglobulin concentration and an increase in frequency of TCM (median of 15%) activated mainly after stimulation with MenC strain. In pre-vaccinated volunteers, 3 of 5 subjects seroconverted 7 or 14 days after administration of the booster dose. There was a significant increase in TCM population 14 days after the booster dose but without differentiated cell activation of control groups. We observed positive response of memory B lymphocyte in most volunteers, but no correlation with bactericidal antibodies. Regarding HIV infected patients, the results showed the need for a second vaccine dose in this population since only about 15% responded to a single dose and second dose resulted in seroconversion in about 55 % of individuals. We observed a positive (r= 0,43) and significant (P= 0,0007) correlation between the opsonizing and bactericidal antibody after vaccination. No significant differences when we relate the titles of bactericidal antibodies with the absolute number of CD4 (P= 0,051) and CD4 nadir (P= 0,09) among patients who seroconverted (n= 43) or not seroconverted (n= 106) after the first dose. Thus, the results indicated that: 1) convalescent patients of DM acquire bactericidal antibodies after infection with N. meningitides; 2) in vaccinated volunteers, the booster dose of anti-MenB vaccine was not fully effective in activating the immune memory by production of bactericidal antibodies or activation of memory CD4 T lymphocyte; 3) HIV-positive patients need a booster dose of the anti-MenC conjugated vaccine.