More antigen-dependent CD4+ T cell / CD4+ T cell interactions are required for the primary generation of Th2 than of Th1 cells

✍ Scribed by Nahed Ismail; Peter A. Bretscher

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 110 KB
• Volume: 31
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/1521-4141(200106)31:6<1765::aid-immu1765>3.0.co;2-t

✦ Synopsis

Mechanisms controlling the Th1/Th2 phenotype of a primary immune response are often discussed assuming that the generation of Th1 and Th2 cells from the common CD4 + precursor T helper (pTh) involves an interaction of this pTh cell with an antigen-presenting cell (APC) in the form of a two-cell interaction. Other studies suggest that the outcome of this two-cell interaction is modified by the presence of other T cells. No study has analyzed primary immune responses generated in normal, non-TcR transgenic mice, following the administration of a non-infectious antigen administered without adjuvant. We show that the Th1/Th2 phenotype of such a primary response, generated in lethally irradiated recipients reconstituted with a variety of unprimed spleen cells, depends conjointly on the amount of antigen and number of unprimed syngeneic CD4 + T cells present, with higher amounts and numbers favoring the generation of Th2 cells. Our observations show how these quantitative variables control in an interdependent manner the Th1/Th2 phenotype of a primary immune response, and bear upon the mechanism by which this phenotype is determined.