A sulfated derivative of chitin, namely N-carboxymethyl chitosan-N-O-sulfate (NCMCS), was shown to inhibit uptake and replication of human immunodeficiency virus-1 (HIV-1) in CD4+ human T-lymphoma cells, which was attributed to the interference of NCMCS with the interaction of viral GP120 envelope glycoproteins with CD4+ cell surface receptors [90]. The gene discussed is CD4; the disease is lymphoma.