Lymphocyte inhibitory and chemotactic factors produced by bursal and thymic lymphocytes

Bursal (B) and thymic (T) lymphocytes from chickens sensitized to Mycobacterium tuberculosis (PPD) or human gamma globulin (hGG) produced an avian lymphocyte-inhibitory factor designated as LyIF-PPD or LyIF-hGG, respectively. A chemotactic factor (LCF) for peripheral blood leukocytes was elaborated only by T-cells sensitized to PPD and hGG. These factors were partially purified by HPLC and were characterized physiochemically. Maximum inhibitory activity for LyIF-PPD and LyIF-hGG occurred in peak fractions corresponding to molecular weight ranges of 29,000 to 52,000 daltons and 15,000 to 29,000 daltons, respectively. The inhibitory activity of B- and T-LyIF-hGG was lost after chymotrypsin and neuraminidase treatment. Maximum chemotactic activity for LCF-PPD and LCF-hGG was in peak HPLC fractions corresponding to molecular weight ranges of 9,000 to 16,000 daltons and 8,000 to 16,500 daltons, respectively. Chemotactic activity of LCF-PPD and LCF-hGG was lost following chymotrypsin treatment while it was not reduced after neuraminidase treatment. Both inhibitory and chemotactic activities were stable at 56 C for 30 min and resistant to changes in pH from 5 to 9. The precursor molecule for the lymphokine is made after antigen immunization, but activated in the presence of the sensitizing agent.