Send to

Choose Destination
Proc Natl Acad Sci U S A. 2012 Jun 12;109(24):9511-6. doi: 10.1073/pnas.1202408109. Epub 2012 May 29.

Distinct CD4+ helper T cells involved in primary and secondary responses to infection.

Author information

Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.


Helper T cells are critical for protective immunity, CD8(+) T-cell memory, and CD4(+) recall responses, but whether the same or distinct CD4(+) T cells are involved in these responses has not been established. Here we describe two CD4(+) T cells, LLO118 and LLO56, specific for an immunodominant Listeria monocytogenes epitope, with dramatically different responses to primary and secondary infection. Comparing in vivo responses, LLO118 T cells proliferate more strongly to primary infection, whereas surprisingly, LLO56 has a superior CD4(+) recall response to secondary infection. LLO118 T cells provide more robust help for CD8(+) T-cell responses to secondary infection than LLO56. We found no detectable differences in antigen sensitivity, but naive LLO118 T cells have much lower levels of CD5 and their T-cell receptor levels are dramatically down-regulated after their strong primary response. Thus, distinct CD4(+) helper T cells are specialized to help either in primary or secondary responses to infection.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center