CD3 (Cluster of differentiation 3), originally known as T3, is one of the first groups of human T lymphocyte surface antigens recognized by monoclonal antibodies. It has been reported that antibodies against CD3 could either stimulate T cells to divide or inhibit the progress of effector functions according to the conditions used. It plays an important role in T cell and the CD3 T-cell co-receptor helps to activate the cytotoxic T-Cell and T helper cells. The CD3 molecule is composed of a protein complex and consists of four distinct chains. The complex of mammals contains a CD3γ chain, a CD3δ chain, and two CD3ε chains. All these chains associate with T-cell receptor and the ζ-chain to generate an activation signal in T lymphocytes. Gp41 (Glycoprotein 41) is a subunit of the envelope protein complex of human immunodeficiency virus (HIV), which plays an important role in virus entry. The transmembrane submit protein gp41 with surface subunit gp120 make up the glycoprotein env of HIV, when non-covalently bound to each other (Envelope spike complex). There are three major regions within the gp41 sequence including the cytoplasm domain, the transmembrane domain, and the ectodomain. Its ectodomain contains certain sites required for the infection of host cells. Furthermore, gp41 has two structures of helical repeats that are essential for the viral fusion, heptad repeat 1 (HR1) and heptad repeat 2 (HR2). Since it is crucial in the HIV infection process, gp41 has emerged as an attractive target for drug design.