Expression of immunoglobulin, granzyme-b and perforin against Ag85A and ag85b proteins of mycobacterium tuberculosis in Balb/c mice

Abstract

Background: Ag85 is a protein that may maintain survival of M. tuberculosis in intracellular parts of host cells and is considered as a virulence factor. The expression of Ag85 protein can stimulate proliferation and differentiation of B- cells and T-cells in patients with tuberculosis. This research aimed to determine the ability of Ag85A and Ag85B proteins in activating the response of antibodies, granzyme-B and perforin in Balb/c mice.

Materials and Methods: Twenty-five male Balb/c mice were assigned into five groups. Group I was treated with adjuvant, group II with Bacillus Calmette-Guerin (BCG) vaccine, group III with a combination of BCG and Ag85A, group IV with a combination of BCG and Ag85B and group V with a combination of BCG, Ag85A and Ag85B. Concentrations of immunoglobulin G, granzyme-B and perforin were examined using ELISA and the number of CD8+ T-cells and NK T-cells were checked by flow cytometry.

Results: The highest concentration of immunoglobulin G was found in group V with 62.49±5.4327 ng/ml. The highest mean number of CD8+ T-cells, NK T-cells, granzyme-B and perforin was found in group IV with 4.32%, 1.03%, 35.11 ± 1.7789 pg/ml and 6.19±0.2235 pg/ml, respectively. The results of One-Way ANOVA test showed that there were significant differences in immunoglobulin responses, with p<0.05. The expressions of granzyme-B and perforin were higher in mice treated with combination of BCG and recombinant proteins.

Conclusions: Ag85 protein can be combined with the BCG vaccine to improve protection against M. tuberculosis infection.

Keywords: Ag85A and Ag85B proteins, Immunoglobulin, granzyme B and perforin, TB Vaccine