Disease relevance of inlA

• Differential inlA and inlB expression and interaction with human intestinal and liver cells by Listeria monocytogenes strains of different origins [1].
• When crude E. coli cell lysates were subjected to immunoblot analysis, it was demonstrated that the mAb bound specifically to the heterologously expressed recombinant InlA protein, thus confirming the specificity of the mAb [2].

High impact information on inlA

• One of them is the gene situated directly downstream of inlA, called inlB, which also encodes a leucine-rich repeat protein [3].
• We report the identification of a previously unknown gene, inlA, which is necessary for the gram-positive intracellular pathogen Listeria monocytogenes to invade cultured epithelial cells [3].
• How InlA, InlB, LLO or ActA interact with the mammalian cells is beginning to be deciphered [4].
• DNase I footprint experiments show that purified PrfA protects sequences of dyad symmetry previously proposed as PrfA binding sites in the hly and in the inlA promoter regions [5].
• A mutant of Listeria monocytogenes EGD was constructed that carries an extended deletion removing the entire PrfA-regulated gene cluster from plcA to plcB and a second deletion inactivating the inlA gene [6].

Biological context of inlA

• The results of this study indicate that differential expression levels of inlA and inlB possibly play a role in the virulence capacities of L. monocytogenes strains [1].
• Analysis of sequence data for 120 L. monocytogenes isolates revealed evidence of clustering between isolates from the same source, based on the phylogenies inferred from actA and inlA (P = 0.02 and P = 0.07, respectively; SourceCluster test) [7].
• Secondly, avid invasion was obtained when a strain deleted for inlAB was complemented with a plasmid harbouring inlB only, whereas strains expressing inlA did not enter HUVECs [8].
• Comparison of their nucleotide sequences with that of the corresponding segment of inlA from EGD-e and Scott A strains, taken as epidemic references, showed more divergence [9].
• A PCR-restriction fragment length polymorphism (RFLP) method was developed in order to screen a large number of strains for impaired adhesion to epithelial cells due to expression of truncated InlA. inlA polymorphism was analyzed by PCR-RFLP in order to correlate inlA PCR-RFLP profiles and production of truncated InlA [10].

Anatomical context of inlA

• This observation led us to study the mRNA expression levels of inlA, inlB, and ami, important virulence genes mediating adhesion and invasion of eukaryotic cells, by real-time reverse transcription-PCR for 27 clinical and 37 nonclinical L. monocytogenes strains [1].
• Several bacterial proteins contributing to these events have been identified, including the invasion proteins internalin A (InlA) and B (InlB), the secreted pore-forming toxin listeriolysin O (LLO) which promotes the escape from the phagocytic vacuole, and the surface protein ActA which is required for actin polymerization and bacterial movement [4].
• Strains of serotypes 4c, 4d, 4e, and especially 4a show a low level of invasiveness in Caco-2 cells, which correlates in part with the low level of expression of the inlA gene [11].
• Trophoblast cell culture systems were permissive for listerial growth and cell-to-cell spread and revealed that L. monocytogenes deficient in internalin A, a virulence factor that mediates invasion of nonphagocytic cells, was 100-fold defective in invasion [12].
• Data presented here show that only invasive Listeria sp. have surface InlA and that L. monocytogenes can enter non-listericidal macrophage cell lines by binding of bacterial InlA to the macrophage cell surface [13].

Analytical, diagnostic and therapeutic context of inlA

• A segment of 2,916 bp containing parts of the two genes inlA and inlB in L. monocytogenes was amplified by the PCR technique [14].
• Sequencing of inlA and Western blot analysis confirmed that truncated InlA was expressed in the 10 L. monocytogenes strains which were isolated from food [10].
• Recombinant listeriolysin O and internalin A were used as antigens in an enzyme-linked immunosorbent assay (ELISA) for the specific detection of anti-Listeria monocytogenes antibodies in cattle [15].
• Use of listeriolysin O and internalin A in a seroepidemiological study of listeriosis in Swiss dairy cows [15].
• While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n=76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n=72) contained isolates with and without inlA PMSCs [16].

References