The heterologous prime-boost strategy of live Salmonella vaccine expressing Mycobacterium tuberculosis fusion antigen Age5B-ESAT6 (esxA) from the chromosome followed by a systemic boost of antigen and adjuvant reduced the levels of M. tuberculosis bacteria in the lungs and spleen to the same extent as BCG. Additionally, this vaccination regimen was observed to be statistically equivalent in terms of protection to immunisation with BCG (Hall et al., 2009). In a prophylactic vaccine model, immunization with the Mycobacterium tuberculosis protein ESAT-6 with LANAC adjuvant elicited significant protective immunity against aerosol challenge with virulent M. tuberculosis (Zaks et al., 2006).
Hall et al., 2009: Hall LJ, Clare S, Pickard D, Clark SO, Kelly DL, El Ghany MA, Hale C, Dietrich J, Andersen P, Marsh PD, Dougan G. Characterisation of a live Salmonella vaccine stably expressing the Mycobacterium tuberculosis Ag85B-ESAT6 fusion protein. Vaccine. 2009; 27(49); 6894-6904. [PubMed: 19755145].
Zaks et al., 2006: Zaks K, Jordan M, Guth A, Sellins K, Kedl R, Izzo A, Bosio C, Dow S. Efficient immunization and cross-priming by vaccine adjuvants containing TLR3 or TLR9 agonists complexed to cationic liposomes. Journal of immunology (Baltimore, Md. : 1950). 2006; 176(12); 7335-7345. [PubMed: 16751377].
Rv3875, (MT3989, MTV027.10), len: 95 aa. esxA, early secretory antigenic target (see citations below), identical to Q57165|O84901|ESAT6 EARLY SECRETORY ANTIGENIC TARGET from Mycobacterium bovis (94 aa), FASTA scores: opt: 596, E(): 4.6e-33, (100.0% identity in 94 aa overlap). Also similar to Q50206|ESA6_MYCLE|ESAT6|ESX|L45|ML0049|MLCB628.12c 6 KDA EARLY SECRETORY ANTIGENIC TARGET HOMOLOG (ESAT-6-LIKE PROTEIN) (L-ESAT) from Mycobacterium leprae (95 aa), FASTA scores: opt: 236, E(): 3.3e-09, (36.25% identity in 91 aa overlap); and weak similarity with others proteins ESAT-like from Mycobacterium leprae. Also some similarity with O53266|ES69_MYCTU|Rv3019c|MT3104|MTV012.33c PUTATIVE SECRETED ESAT-6 LIKE PROTEIN 9 from Mycobacterium tuberculosis (96 aa), FASTA scores: opt: 131, E(): 0.03, (26.15% identity in 88 aa overlap); and other ESAT-like protein. Contains probable coiled-coil from 56 to 92 aa. BELONGS TO THE ESAT6 FAMILY. Note that previously known as esat-6.; esat-6
Protein Annotation
FUNCTION: Not known. Elicits high level of IFN-gamma from memory effector cells during the first phase of a protective immune response (UniProt: P0A564)
SUBCELLULAR LOCATION: Secreted protein (UniProt: P0A564)
SIMILARITY: Belongs to the ESAT-6 (esx) family (UniProt: P0A564)
Protein Sequence
>YP_178023.1 ESAT-6 protein EsxA [Mycobacterium tuberculosis H37Rv]
MTEQQWNFAGIEAAASAIQGNVTSIHSLLDEGKQSLTKLAAAWGGSGSEAYQGVQQKWDATATELNNALQ
NLARTISEAGQAMASTEGNVTGMFA
