Early commitment of adoptively transferred CD4(+) T cells following particle-mediated DNA vaccination: implications for the study of immunomodulation

The early responses of CD4(+) T cells to particle-mediated DNA immunisation were investigated using OVA-specific TCR-transgenic CD4(+) T cells. Follow ing adoptive transfer of these cells, mice were immunised by delivery into the skin of a plasmid encoding ovalbumin. Transgenic T cells underwent a ra pid and transient antigen-specific activation, followed by clonal expansion (up to similar to 6% of total lymphocytes). Immunisation with ovalbumin in CFA evoked similar responses with slightly faster kinetics. Numerous antig en-specific T cells synthesising IFN-gamma (Th1) and IL-4 (Th2) were detect able using both intracellular staining and ELISPOT assays. This study provi des a quantitative analysis of both T cell proliferation and Th1/Th2 balanc e following particle-mediated DNA immunisation and establishes a robust and sensitive model in which to assess modulation of helper T cell responses i n DNA vaccination. (C) 2001 Elsevier Science Ltd. All rights reserved.