Effects of sarcolectin (SCL) on human peripheral blood mononuclear cells

Sarcolectin (SCL) is a tissue growth factor found in various human or animal tissues, functioning in balance with interferons (IFNs) that can inhibit growth and affect cell differentiation. Like somatotropin, SCL is found in the pituitary gland. In humans, the SCL gene is located on chromosome 12 (q12-q13) and expressed as a 55 kDa protein consisting of 469 amino-acids. After a single activation of peripheral blood mononuclear cells (PBMC) obtained from more than 30 individuals, highly significant cell proliferation was found to peak after 7 days in culture. The presence of adherent cells was necessary for cell proliferation. SCL induced over-expression of α-IL-2 receptor (CD25) leading to proliferation of CD3+/CD4+/CD45RO+ T cells. Thus in PBMC, SCL induced CD4+ T cell growth and expression of inflammatory cytokine genes, including TNF-α, IL-1β, IL-6 and IL-8. IFNs are also produced following activation as a feedback response which is maintained for about 20 days.