This invention described peptide constructs that may be of clinical importance in HIV/AIDS vaccine development. A vaccine for the prevention and/or treatment of HIV infection would ideally elicit a response in a broad range of the population. It would also have the capability of inducing high titered neutralizing antibodies, cytotoxic T lymphocytes, and helper T cells specific for HIV-1 gp 160 envelope protein. A vaccine based on the synthetic or recombinant peptides has been developed which elicits these responses while avoiding the potential safety risks of live or killed viruses. Unlike previously developed vaccines, this invention avoids those regions of gp 160 which may contribute to acceleration of infection or the development of immune deficiency. Peptides having high activity in the eliciting of a cytotoxic T lymphocyte response to the HIV-1 envelope glycoprotein gp160 are described. The activation of 12-15 residue peptides by proteolytic degradation to shorter peptides is shown as are general techniques for characterizing such activation processes. The peptide described is recognized by both human and murine cytotoxic T lymphocytes, and is immunodominant in H-2d mice such as BALB/c, B10.D2, DBA/2, etc. This makes it ideal for determining responses in animal models preclinically before use in human trials. It is also ideal for detecting cytotoxic T lymphocyte responses to HIV envelope in these strains of mice.