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Low IgG2 and polysaccharide response in a T cell receptor expression defect
J R Regueiro1, P Perez-Aeiego, P Aparicio
1Department of Pediatry, Hospital 12 de Octubre, Madrid, Spain.
European Journal of Immunology
|November 1, 1990
Summary
Individuals with T cell receptor (TcR) defects surprisingly maintained normal antibody production to protein antigens. However, impaired responses to polysaccharides and selective IgG2 deficiency suggest T cell involvement in these specific immune responses.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- B lymphocyte antibody synthesis relies on T lymphocyte cooperation, typically initiated by T cell receptor (TcR) engagement.
- Immunodeficiencies can arise from various genetic defects affecting immune cell function.
Observation:
- A novel immunodeficiency characterized by a TcR expression defect was studied in two siblings.
- Despite the TcR defect, the siblings exhibited normal in vivo antibody responses to protein antigens.
- Impaired responses to polysaccharide antigens and a selective IgG2 deficiency were observed.
Findings:
- B lymphocyte phenotype and function were normal in vitro, ruling out gross B cell dysfunction.
- A T cell line from a sibling showed abnormal TcR expression but retained normal TcR-mediated functions.
- The study suggests that even with low TcR expression, T cells can provide sufficient help for protein antigen responses.
Implications:
- Certain polysaccharide responses may be more T cell-dependent than previously understood.
- T cell dysfunctions, not Ig gene deletions, could be the cause of some IgG2 deficiencies.
- This research highlights the critical role of T cell function in specific antibody responses and immunodeficiency.