AUTOSTEREOGRAM - Single Image Stereogram (SIS). To see the stereo effect, please gaze at infinity at the pattern above. A 3D image should eventually appear to float in front of the screen. Human Immunodeficiency Virus particles (or virions): are covered by projecting spikes (or knobs). These consist of trimeric envelope proteins that help the virus to attach to target cells. They comprise gp120 (outer knob) and gp41 (stalk, trans-membrane section, and cytoplasmic tail). Next comes the viral envelope derived from the host cell plasma membrane during budding of the virus particle. The viral envelope is effectively the viral surface. |