HIV Envelope Protein Infects Host Cell (image) Duke University Caption This illustration shows how the envelope proteins covering the surface of an HIV virion (1, 2) bind to a host cell (3, 4). The trimeric MPER region of gp41 is shown in red and can be disabled by antibodies, shown in light blue. Credit Marian Miller Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.