1 Most of these diseases are infections, caused by a variety of bacteria, viruses, and parasites that can be foodborne. 2  Other diseases are poisonings, caused by harmful toxins or chemicals that have contaminated the food, for example, poisonous mushrooms.
(cluster designation 4) symbol for a glycoprotein expressed on the surface of helper T lymphocytes and other immune cells. CD4 serves as a receptor for human immunodeficiency virus envelope glycoprotein gp120.
How HIV Infects a Cell. HIV is a retrovirus, which means it carries single-stranded RNA is its genetic material rather than the double-stranded DNA human cells carry. Retroviruses also have the enzyme reverse transcriptase, which allow it to copy RNA into DNA and use that DNA copy to infect human, or host, cells.When HIV infects a cell, it first attaches to and fuses with the host cell.Then the viral RNA is converted into DNA and the virus uses the host cellâs machinery to replicate itself during a process called reverse transcription. The new copies of HIV then leave the host cell and move on to infect other cells.IV is a retrovirus, which means it carries single-stranded RNA is its genetic material rather than the double-stranded DNA human cells carry.