The dipeptide Lys-Pro restores the diminished wound healing following treatment with anti-T-helper cell monoclonal antibody.

To determine the role of T-cell subsets in wound healing, we studied the granulation tissue proliferation after depletion of CD4 or CD8 positive cells. Granulation tissue proliferation in CD8-diminished AB mice was significantly higher than in the control group as a result of depleted suppressor cell activity. The CD4-depleted mice produced granulation tissue in less than 30% of the control group. To investigate the role of dipeptidylpeptidase IV on CD4 positive cells in wound healing we used Lys-[Z(NO2)]-Pro, a chemically modified dipeptide which may result by degradation of polypeptides by this peptidase. It was possible to restore the diminished capability of granulation tissue proliferation in CD4-depleted mice by a single treatment with the dipeptide Lys-[Z(NO2)]-Pro. Our results suggest that: (i) the CD4 positive T-helper subset regulates wound healing, and (ii) products of degradation by dipeptidylpeptidase IV may bypass T-helper cell function.