Much remains to be learned regarding anti-HLA antibodies in transplantation. A few of the examples where additional knowledge is needed include: 1) Factors that influence the marked variations in clinical phenotypes exhibited by antibody-mediated processes, 2) Processes that determine whether cellular or humoral mechanisms (or both) predominate in the alloresponse to human allografts, 3) Factors that influence antibody production, and responses to antihumoral therapies, 4) the extent to which antibody elimination is needed to achieve optimal results with antihumoral therapies.

What You'll Take Away from His Talk:

• Accumulation of knowledge regarding anti HLA alloantibodies in transplantation is proceeding at a fast pace.
• Requisite basic science in mice and humans is substantial but a broader and deeper understanding is needed.

New approaches for characterizing HLA antibodies are transforming organ allocation and impacting clinical practice. Recent accomplishments, current controversies and opportunities to advance the field will be discussed.

What You'll Take Away from Her Talk

• Improvements in histocompatibility testing have dramatically improved the efficiency of allocating organs from deceased donors and benefited highly sensitized patients.
• Many factors that are not routinely measured are likely contribute to the effect of HLA antibodies in transplantation.

B cells and plasma cells mediate functions critical to transplant success, including antibody production and antigen presentation, as well as positive and negative immunoregulatory activities. Understanding how the size and composition of pre-immune and antigen-experienced B cell niches are regulated should enable targeted prophylactic and therapeutic interventions. This presentation will overview current thought about the establishment and regulation of these different niches, highlighting emerging ideas relevant to their clinical manipulation.

What You'll Take Away from His Talk:

• Pre-immune and antigen experienced B cell subsets occupy independent homeostatic niches.
• Selection and survival in each niche is mediated by different key molecular families and signaling systems. These include the B cell antigen receptor complex, BLyS (BAFF) family members, and other positive and negative regulators.
• Targeting appropriate members of these molecular families may allow the selective manipulation of B cell subsets to clinical advantage.

• Can Bregs be identified and induced to promote allograft tolerance and does TIM-1 play a functional role?
• Can Bregs be separated from proinflammatory B cells subsets with opposing activity?
• How do Bregs and proinflammatory B cells correlate with renal allograft function in humans?

The major question that I will address in my talk is how B cells regulate CD4 and CD8 T cell responses. We will show that B cells regulate T cell responses by both antibody dependent and independent mechanisms and therefore are important modulators of cellular immunity in the context of infection, autoimmunity and transplantation.

What You'll Take Away from Her Talk:

• B cells regulate primary and memory CD4 and CD8 T cell responses via antibody independent mechanisms.
• Antibody and antibody immune complexes can regulate DC-mediated development of CD8 memory responses to some, but not all, antigens.