The research team, led by Mayo Clinic immunologists Marilia Cascalho, M.D., Ph.D., and Jeffrey Platt, M.D., report in this month's Journal of Immunology that B cells, the lymphocytes that produce antibodies, help to generate T cells, the lymphocytes that fight viruses and tumors.
"Previously, it was thought that B cells and T cells, two components of immunity produced by the lymphatic tissues, develop independently until they eventually came together to fight microbes or to eliminate infected cells in the body," says Dr. Cascalho. "Now we know that the B cells and the immunoglobulin that they produce can help reconstitute immunity by promoting the development of T cells." For immunity to work it is crucial that there are enough T cells and also that the T cells be diverse so they are able to respond to many different threats. B cells help to make the T cells in the body diverse. Immunoglobulin is a specialized protein that acts as an antibody.
Diversity of lymphocyte receptors is thought to be the key to immunity. A cell's receptor is the portion that makes it selectively bind with another substance. The more diverse T cell receptors are, the more likely it is T cells of the appropriate specificity will be present to combat today's sophisticated viruses or evasive bacteria. This flexibility and corresponding T cell receptor diversity are absent in patients with immunodeficiency diseases and in some who have cancer or receive cancer treatment. AIDS patients, for example, may have very few T cells and those T cells they have may not be diverse. The report by Dr. Cascalho's group s