A T lymphocyte that amplifies the activity of B lymphocytes, other T lymphocytes, and macrophages. Once a helper T lymphocyte recognizes an antigen, it divides and its progeny start to synthesize and secrete a variety of lymphokines (q.v.). These cause B lymphocytes to divide and differentiate into plasma cells, inactive precursor T cells to develop into cytotoxic T lymphocytes, and macrophages to be recruited and activated. See AIDS, cytotoxic T lymphocyte, T lymphocyte.
Subjects: Genetics and Genomics.