Re: How many white blood cells does it take to destroy a bacteria cell?

There isn't a strict ratio of white blood cells to bacteria, the whole 
immune system acts in concert to destroy infectious pathogens, whether 
they are bacteria, viruses, parasites or fungi.

The immune response can be divided into three general "branches", which 
interact and cooperate. Innate immunity is the part of the immune response 
that we all have, such as the skin that protects our inner organs. Humoral 
immunity is the antibody response to infectious diseases, and cellular 
immunity is (as it sounds) the cellular response. Cellular immunity is 
traditionally thought of as the cellular response to viruses. The 
antibodies that comprise the humoral immune response, however, are 
produced by a particular type of white blood cell, the "B" lymphocyte. B 
lymphocytes are activated and controlled by "T" lymphocytes, which are in 
turn activated by macrophages and dendritic cells. Macrophages and 
dendritic cells occupy a unique place in the immune response, serving as 
an integral part of all three branches: innate, cellular, and humoral. 
Macrophages literally "eat" bacteria, digesting them and presenting 
portions of them to T lymphocytes. At the same time, B lymphocytes pick up 
pieces of the bacteria as well and, in conjuction with signals from T 
lymphocytes, are then activated to produce antibodies against the 
bacteria. The antibody binds to the bacteria and, in turn, makes it easier 
for the macrophages to kill and digest the bacteria!

So when you think of your immune response against a disease, whether it is 
caused by a virus or a bacteria, think of the response as a team working 
together to fight off the disease.