He had been studying macrophages since the early 1970's, trying to understand how they killed infected cells.

"You're seeing infected glial cells, at least the relevant groups."

The immune system actually attacks infected cells rather than the virus, he explained.

It is found in the membranes of infected cells, but not the virus particles themselves.

However a decrease in the rate of cell growth is seen in the infected cells.

Some viruses cause no apparent changes to the infected cell.

In this way, one infected cell soon becomes billions.

The infected cells develop in the marrow, then are carried by the bloodstream to the rest of the body.

This causes the infected cells to divide and form a nodule.

This gets detected by the immune system, which then eliminates the infected cell.