| | Re: Plasma cells in circulating blood.
As foreword, B cell, such as other immune cells, in body are present in two development steps : a) resting/naive and primed/memory. The first (small lymphocytes) is located in spleen, and those circulating are trapped in lymph nodes, while primed/memory B cell are located in whole body, blood included. When you cultivate PBMC's in stimulating medium (PHA, PWM/ConA and others) are activated primed/memory B cell, that in few days are modified in plasma blast and then in plasma cell with Ig production/secretion. In Aristotle philosophy egg (B cell) to be a potential chicken (plasma cell).
Question : I culture PBMCs (peripheral blood mononuclear cells) and I wonder if I have memory B cells in the culture. I know that there is almost no plasmacytes coz their per cent in full blood is very low. What about memory B cells ?
Answer : Yes, B memory cell is present in peripheral blood that, only following to stimulation they will become plasma cell.
Question : If I stimulate Th cells in culture only with anti-CD3 and thanks to their stimulation B cells are also stimulated so is it possible that memory B cells will response?
Answer : Yes, anti-CD3 reacts with receptor present on the surface of the T cell that induces production of different cytokines among which IL-2 play a fundamental role for activation of B cell
Question : Is anti-CD3 stimulation a secondary response for memory B cells?
Answer : With reference to the stimulation, the B cell response is surely secondary
Question : Anti-CD3 binds TCR on Th so is this sth new for them or normal situation coz they always catch sth through TCR?
Answer : Anti-CD3 bound CD3 receptor that is part of the TCR core that activates a series of kinase conducting to the activation of nuclear factor that brings to the synthesis of different cytokines and relative receptors. They can act in an autocrine manner, affecting the behavior of the cell that releases the cytokine, or in a paracrine manner, affecting the behavior of adjacent cells.
Question : I think it is sth new coz they won't find sth so ideally similat to anti-CD3 in nature so even if I have memory B cells in culture they won't react on that.
Answer : Ideally, absence of one specific stimulating for TCR doesn't allow the secretion of inductors on the B cell and therefore their stimulation. Nevertheless we are speaking of "in vitro" cultivation in which different exogenous factors (contact with the glass, quality/quantity of elements in medium, pH, growth factors [e.g.: FCS or AB human serum, transferrin, etc. ], etc.) can to determine direct or indirect spurious activation that it generally constitutes the background of the assay.
I hope to have been exhaustive
Postscript : I like your nick name, are in love with B cell ? At soon