PMID:14500520

Citation	Vakevainen, M, Greenberg, S and Hansen, EJ (2003) Inhibition of phagocytosis by Haemophilus ducreyi requires expression of the LspA1 and LspA2 proteins. Infect. Immun. 71:5994-6003
Abstract	Haemophilus ducreyi previously has been shown to inhibit the phagocytosis of both secondary targets and itself by certain cells in vitro. Wild-type H. ducreyi strain 35000HP contains two genes, lspA1 and lspA2, whose encoded protein products are predicted to be 456 and 543 kDa, respectively. An isogenic mutant of H. ducreyi 35000HP with inactivated lspA1 and lspA2 genes has been shown to exhibit substantially decreased virulence in the temperature-dependent rabbit model for chancroid. This lspA1 lspA2 mutant was tested for its ability to inhibit phagocytosis of immunoglobulin G-opsonized particles by differentiated HL-60 and U-937 cells and by J774A.1 cells. The wild-type strain H. ducreyi 35000HP readily inhibited phagocytosis, whereas the lspA1 lspA2 mutant was unable to inhibit phagocytosis. Similarly, the wild-type strain was resistant to phagocytosis, whereas the lspA1 lspA2 mutant was readily engulfed by phagocytes. This inhibitory effect of wild-type H. ducreyi on phagocytic activity was primarily associated with live bacterial cells but could also be found, under certain conditions, in concentrated H. ducreyi culture supernatant fluids that lacked detectable outer membrane fragments. Both the wild-type strain and the lspA1 lspA2 mutant attached to phagocytes at similar levels. These results indicate that the LspA1 and LspA2 proteins of H. ducreyi are involved, directly or indirectly, in the antiphagocytic activity of this pathogen, and they provide a possible explanation for the greatly reduced virulence of the lspA1 lspA2 mutant.
Links	PubMed PMC201102
Keywords	Animals; Bacterial Adhesion; Bacterial Proteins/genetics; Bacterial Proteins/physiology; Cell Line; Erythrocytes/immunology; Gene Expression; Genes, Bacterial; HL-60 Cells; Haemophilus ducreyi/genetics; Haemophilus ducreyi/immunology; Haemophilus ducreyi/pathogenicity; Haemophilus ducreyi/physiology; Hemagglutinins/genetics; Hemagglutinins/physiology; Humans; Lectins; Mice; Microspheres; Opsonin Proteins/metabolism; Phagocytosis; Sheep; Staining and Labeling; U937 Cells
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HAEDU:Q93Q08		GO:0050765: negative regulation of phagocytosis	ECO:0000315:		P		Enables resistance to phagocytosis along with LspA1. Figure 5. The lspA1 lspA2 mutant lost ability to resist phagocytosis.	complete
HAEDU:Q9ZHL3		GO:0050765: negative regulation of phagocytosis	ECO:0000315:		P		Enables resistance to phagocytosis along with LspA2. Figure 5. The lspA1 lspA2 mutant lost ability to resist phagocytosis.	complete
HAEDC:Q9ZHL3		GO:0009405: pathogenesis	ECO:0000315:		P		Fig 5 shows the resistance to phagocytosis of wild-type and mutant strains of H. ducreyi. The wild-type strain is resistant to phagocytosis.	complete
HAEDC:Q9ZHL3		GO:0020012: evasion or tolerance of host immune response	ECO:0000315:		P		Figures 1 and 2 show the ability of the LspA1 mutant to inhibit the phagocytic activity of HL-60 and U-937, respectively. The LspA1 mutant, shown in column 3, is very like the wild type (column 1).	complete CACAO 5350
HAEDC:Q9ZHL0		GO:0052200: response to host defenses	ECO:0000315:		P		Figures 1 and 2 show the ability of the LspA2 mutant to inhibit the phagocytic activity of HL-60 and U-937, respectively. The LspA2 mutant, shown in column 4, is very like the wild type (column 1).	complete CACAO 5351

References

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