Nucleotide sequence of the 32 kDa-protein gene (antigen 85 A) ofMycobacterium bovisBCG

Abstract

Proteins of the antigen 85 complex are abundantly secreted into the culture supematant of a variety of mycobacteria (1, 2). These proteins are known to be responsible for the high affinity of mycobacteria to fibronectin (3). The 32 kDa protein (antigen 85A) appears to be a major stimulant of cellular and humoral immunity towards mycobacteria both in mice and man (4-6). The gene encoding the 32 kDa protein of Mycobacterium tuberculosis has recently been identified by us (7).Comparison of this gene with the a-antigen from M. bovis BCG (Tokyo) (also referred to as antigen 85B or as MPB 59 protein (8)) revealed 73.8% homology between coding regions of the DNA sequences (7, 9). This figure should be corrected to 77.5% considering that both sequences have been revised since their publication (10, and this report). It is of interest that the homology is limited to the region coding for the mature protein and the carboxy-terminal part of the signal sequences.After screening a Xgtl 1 BCG library (prepared from M. bovis BCG strain 1173P2) with a 5'-230 bp PstI fragment from our M. tuberculosis 32 kDa protein gene (7) (see Figure 2)

Mechanism of interaction of the 85B secreted protein of Mycobacterium bovis with fibronectin

“…Although the antigens are genetically distinct, they are highly homologous and cross-react with polyclonal and monoclonal antibodies raised against individual components (26). The genes encoding antigen 85A, a 32-kDa protein also referred to as P32, have been cloned from M. bovis BCG (5) and M. tuberculosis (3), while genes for 85B, a 30to 31-kDa protein variously termed MPB59 or alpha antigen, have been isolated from M. bovis BCG (10), Mycobacterium kansasii (11), and Mycobacterium leprae (24). Sequence analysis * Corresponding author.…”