passages.id: split_4_test_288_passage
passages.type: progene_text
passages.text: We then constructed chimeric gag genes , which carry the hypervariable V3 region of HIV-1 gp120 , because the V3 loop is known to interact with chemokine receptor as a coreceptor , and known to induce the major neutralizing antibodies and stimulate the cytoxic T lymphocyte responses in humans and mice .