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Mannose-binding lectin enhances the attachment and phagocytosis of mycobacteria in vitro

100%

Bonar A., Chmiela M., Rudnicka W., Rozalska B.

Archivum Immunologiae et Therapiae Experimentalis

2005

vol. 53

issue 5

437-441

Phagocytosis is the critical first step in the Mycobacterium (M.) tuberculosis-phagocyte interaction. The process involves microbial ligands and phagocyte surface receptors. It is known that serum mannose-binding lectin (MBL), an innate immune system component, may enhance the uptake of microbes by phagocytic cells and activate the complement system. Since phagocytes are the replicative environment for mycobacteria and, as we described earlier, tuberculosis patients differ from controls in serum MBL level, we asked whether MBL plays a role in promoting M. tuberculosis access to phagocytic cells. To estimate the influence of MBL on the phagocytic process, FITC-labeled Mycobacterium bovis BCG was used as a model bacterium. Neutrophils from healthy individuals were used as phagocytes. Phagocytosis was performed in the presence or absence of recombinant MBL (rMBL; 2 or 20 g/ml). The activation of complement was determined by dot-blot immune assay with monoclonal antibodies against C5b-C9. We showed that phagocytosis of the bacteria was more intensive in the presence of human rMBL. Both attachment and ingestion of mycobacteria were enhanced when MBL and active complement components (fresh serum) were present in the medium. The dot-blot method showed that the bacteria slightly activated complement by themselves. This effect was enhanced in the phagocyte-bacteria co-cultures containing rMBL.It is possible that MBL may serve in vivo as one of the factors facilitating the entry of mycobacteria into phagocytes, pathogen spread, and the establishment of infection.

Lack of relationship between serum content of MBL, sCD14, anti-PPD and anti-Hsp65 IgG, and ingestion of Mycobacterium bovis BCG bacilli by phagocytes

64%

Paziak-Domanska B., Bonar A., Kowalewicz-Kulbat M., Klink M., Kowalski M., Karhukorpi J., Karttunen R., Jurkiewicz M., Rozalska B., Rudnicka W.

Archivum Immunologiae et Therapiae Experimentalis

2002

vol. 50

issue 5

337-344

Prophylactic vaccination against tuberculosis (TB) with a live attenuated strain of Mycobacterium bovis Bacille Calmett?e-Gerin (BCG) has been used worldwide. However, TB remains one of the most significant diseases of humans and animals. Better understanding of the mechanisms of human immunity to mycobacteria is essential for development of new vaccines and estimation of their efficacy. In this study we determined the levels of known humoral mediators of mycobacterial phagocytosis - mannose binding lectin (MBL), soluble CD14 (sCD14), antibodies of IgG class against mycobacterial purified protein derivative (PPD) and mycobacterial Hsp65 antigen, in the sera from healthy young volunteers vaccinated with BCG and presenting positive and negative Mantoux responses to PPD. Than we asked a question as to whether macrophages and polymorphonuclear leukocytes (PMNs) from the individuals with positive (TT(+)) and negative (TT(-)) tuberculin tests differ by the ability to ingest mycobacteria. Also we were looking for a relation between the intensity of mycobacterial ingestion by phagocytes in the medium with autologous sera containing different concentration of MBL, sCD14 andf anti-mycobacterial IgG. We found no significant differences between the investigated parameters for TT(+) and TT(-) volunteers. Our result suggest that ability of macrophages and PMNs to ingest mycobacteria depends on an individual intrinsic capacity of phagocytes.

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2 Archivum Immunologiae et Therapiae Experimentalis

1 2005

1 2002

2 Bonar A.

2 Rozalska B.

2 Rudnicka W.

1 Chmiela M.

1 Jurkiewicz M.

1 Karhukorpi J.

1 Karttunen R.

1 Klink M.

1 Kowalewicz-Kulbat M.

1 Kowalski M.

1 Paziak-Domanska B.

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Mannose-binding lectin enhances the attachment and phagocytosis of mycobacteria in vitro

Lack of relationship between serum content of MBL, sCD14, anti-PPD and anti-Hsp65 IgG, and ingestion of Mycobacterium bovis BCG bacilli by phagocytes