Staphylococcal cell membrane antigen, a possible antigen in post-methicillin resistant Staphylococcus aureus (MRSA) infection nephritis and IgA nephropathy, exhibits high immunogenic activity that is enhanced by superantigen.
BACKGROUND
The post-methicillin resistant Staphlylococcus aureus (MRSA) infection nephritis is a progressive glomerulonephritis that occurs following Staphylococcus aureus infection. It has been assumed that staphylococcal superantigens and other cellular antigens are necessary for the development of post-MRSA infection nephritis, and we have previously identified a staphylococcal cell membrane antigen (GenBank, accession number; BAB41819.1) as a possible antigen in post-MRSA infection nephritis. In this study, we assessed the immunogenic activity of the staphylococcal cell membrane antigen and determined the relationship between the cell membrane antigen and superantigen.


METHODS
Balb/c mice were immunized with glutathione S-transferase (GST) or staphylococcal cell membrane antigen-GST fusion protein. One week later, their lymphocytes were cultured with or without toxic shock syndrome toxic-1 (TSST-1) for one week. Immunoglobulin levels in the culture supernatants were measured by ELISA, and transcript expressions for cytokines, and the T-cell receptors (TCR) Vbeta17 (activated by TSST-1), Vbeta1 and Vbeta8 (not activated by TSST-1) in the culture were analyzed by reverse transcriptase polymerase chain reaction.


RESULTS
Neither IgG nor IgA were detected in the culture supernatant of GST-primed lymphocytes, with or without TSST-1. In contrast, IgG and IgA levels gradually increased in direct proportion to the TSST-1 concentration in the supernatants of staphylococcal cell membrane antigen-GST fusion protein-primed lymphocytes. Various cytokine messenger RNA (mRNA) transcripts were detected in both GST-primed and staphylococcal cell membrane antigen-GST-primed cells in the presence of TSST-1. A Vbeta17 transcript could not be detected during the early culture phase under both culture conditions, while Vbeta1 and Vbeta8 T-cells survived for 7 days in the staphylococcal cell membrane antigen-GST fusion protein-primed culture in the presence of TSST-1.


CONCLUSIONS
These results suggest that staphylococcal cell membrane antigen-GST-primed T-cells were stimulated more than GST-primed cells. Their activity was enhanced further in the presence of cytokines, which were induced by TSST-1, such that the T-cells were able to survive and activate B-cells to produce immunoglobulins.
Shimizu
Yoshio
Y
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. y-shimz@md.tsukuba.ac.jp
Sakurai
Hideko
H
Hirayama
Kouichi
K
Seki
Masanori
M
Yoh
Keigyou
K
Yamagata
Kunihiro
K
Koyama
Akio
A
D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D005922:Glomerulonephritis, IGA / Q000276:immunology* / Q000382:microbiology; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D066298:In Vitro Techniques; D016106:Methicillin Resistance / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009393:Nephritis / Q000276:immunology* / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000276:immunology*; D018089:Superantigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology
D001427:Bacterial Toxins; D016207:Cytokines; D004768:Enterotoxins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal