Doc Begely.

Next time make sure you have your facts straight, you've just embarrassed our whole team in front of this Doctor. Doc Begely's answer is completely factual, you just need to listen carefully. Now, you might be thinking that he is wrong in saying that only B-cells circulate through the blood stream, but you missed a key word, continuously. While T-cells do circulate through the blood stream regularly, they also travel into the body tissues. B-cells, on the other hand, are strictly restricted to the fluids of the body. Looks like you need to study. Try to learn the basics first.