Fibronectin binding protein A of Staphylococcus aureus can mediate human T lymphocyte adhesion and coactivation.
The extracellular matrix protein fibronectin (FN) mediates the adhesion of bacteria as well as T lymphocytes. Mammalian cells express integrins alpha(4)beta(1) and alpha(5)beta(1) as the major FN-binding cell surface receptors. Bacteria such as Staphylococcus aureus, also express FN-binding receptors that are important for adherence to host tissue and initiation of infection. The S. aureus FN-binding protein, FnbpA, has been previously identified, and recombinant proteins that correspond to distinct functional regions of this protein have been made. Three recombinant truncated forms of FnbpA, rFnbpA(37-881), rFnbpA(37-605), and rFnbpA(620-881), were examined for effects on in vitro adhesion and coactivation of human T lymphocytes. These proteins, when coimmobilized with anti-CD3 mAb, activated T lymphocyte proliferation. The coactivation signal generated by the rFnbpA proteins required medium containing serum with FN. Furthermore, the costimulatory signal could be restored in FN-depleted serum when the rFnbpAs were preloaded with soluble FN. Monoclonal Ab blocking studies revealed that integrin alpha(5)beta(1) is the major receptor responsible for the rFnbpA costimulatory signal. Shear flow cell detachment assays confirmed that lymphocytes can bind to FN captured by the rFnbpA proteins. These results suggest that the S. aureus rFnbpA can interact with integrin alpha(5)beta(1) via an FN bridge to mediate adhesion and costimulatory signals to T lymphocytes.
Miyamoto
Y J
YJ
Department of Immunology, University of Texas M. D. Anderson Cancer Center, and Center for Extracellular Matrix Biology, Albert B. Alkek Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030, USA.
Wann
E R
ER
Fowler
T
T
Duffield
E
E
Höök
M
M
McIntyre
B W
BW
D018829:Adhesins, Bacterial; D000276:Adjuvants, Immunologic / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005312:Fetal Blood / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology; D006801:Humans; D019169:Jurkat Cells; D020014:K562 Cells; D008213:Lymphocyte Activation / Q000276:immunology*; D016853:Muromonab-CD3 / Q000494:pharmacology; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D017469:Receptors, Fibronectin / Q000502:physiology; D011994:Recombinant Proteins / Q000276:immunology / Q000494:pharmacology; D012995:Solubility; D013211:Staphylococcus aureus / Q000276:immunology / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000382:microbiology* / Q000502:physiology
D018829:Adhesins, Bacterial; D000276:Adjuvants, Immunologic; D001426:Bacterial Proteins; D002352:Carrier Proteins; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D005353:Fibronectins; D016853:Muromonab-CD3; D010446:Peptide Fragments; D017469:Receptors, Fibronectin; D011994:Recombinant Proteins; C078635:fibronectin-binding proteins, bacterial