HIF-1α regulates the expression of the non-conventional isoform of the cd5 gene in T cells under the hypoxic condition: A potential mechanism for CD5neg/low phenotype of infiltrating cells in solid tumors

•Surface CD5 expression gets reduced due to exonal switch from E1A to E1B exons.•Hypoxia response elements (HREs) are present in the upstream of E1B exon.•Binding of HIF-1α onto these HREs increased E1B mRNA expression in hypoxic T cells.•This resulted in increased cytoplasmic accumulation of CD5 in hypoxic T cells.•Hypoxia exposure may result in sCD5low/neg infiltrated T cells in solid tumors.