Mycobacterium tuberculosis antigens MPT63 and MPT83 increase phagocytic activity of murine peritoneal macrophages.

A A Siromolot,O S Oliinyk,S V Komisarenko,D V Kolibo

doi:10.15407/ubj88.05.062

Abstract

Macrophages (MΦ) are the most described and characterized target and host of mycobacteria. Like other cells of innate immunity MΦ have a wide range of receptor molecules which interact with different pathogen associated molecular patterns (PAMPs). Immunodominant proteins MPT63 and MPT83 that are synthesized in abundance by Mycobacterium bovis or Mycobacterium tuberculosis strains could be involved in development of tuberculosis infection. The aim of this study was to search for effects of these mycobacterial antigens on target cells. For this aim full-sized sequences of MPT83 (rMPT83full) and MPT63 antigens were cloned into plasmid pET24a(+). The increase of phagocytic activity of murine peritoneal macrophages was demonstrated, but not of macrophage-like cells from J774 cell line, which were treated by rMPT63 and rMPT83full proteins for 24 h. This effect of such antigens can be considered as a way to facilitate the consumption of mycobacterial cells by macrophages to avoid other effector mechanisms of innate and adaptive immunity.

Highlights

K nowledge about mechanisms of pathogene sis and development of tuberculosis (TB) is rapidly growing
The recombinant MPT63 isolated from Escherichia coli and natural protein of M. tuberculosis MPT63 did not differ by the results of serological tests [6, 7]
In the current study we focused on the effects of rMPT63 and rMPT83full on macrophages phagocytosis activity

Summary

Introduction

K nowledge about mechanisms of pathogene sis and development of tuberculosis (TB) is rapidly growing. Identification of cellular and molecular targets for immunodominant proteins MPT63 and MPT83 could fill certain gaps in understanding the mechanism of tuberculosis pathogenesis. It remains unclear whether some M. tuberculosis antigens, including MPT63 and MPT83, are involved in avoiding bacteria degradation in endosomes. MPT63 is 16kDa secreted protein that had relatively high expression level in mycobacteria. This antigen was obtained from M. tuberculosis culture fluid in 1991 by Nagai and colleagues [4]. MPT63 from M. tuberculosis have difference of one nucleotide in their gene sequences but are not distinguished in functional products. The recombinant MPT63 isolated from Escherichia coli and natural protein of M. tuberculosis MPT63 did not differ by the results of serological tests [6, 7]

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Results