The Heterogeneity of B-cell Memory and Vaccine Design

The establishment of long-term humoral memory to a pathogen is an important goal of vaccination. One of the important component of it is belong to memory B cells. This cells will help us from the future re-attack of pathogens by surveying their specific antigen in the periphery for affinity maturation. Classically the marker for B cell memory was expressed by CD27. However recent finding suggest the heterogeneity of the memory compartment that involving CD27- memory B cells. If a vaccine has been designed to non-specific memory B cell, it potentially will result in loss of maintenance and/or establishment of an important subset of memory populations. Consequently, this will lead to improper localization and ineffective response that result in loss of vaccine efficacy. Therefore it would be challenging to study the environment that create this subset memory cells and to understand their property in vivo for the better vaccine design.

Reference:
http://www.frontiersin.org/b_cell_biology/10.3389/fimmu.2011.00077/full

Screening for Allergy Vaccine Candidates

Many people suffer from various allergies and have asthma triggered by certain particles found in our environment. Wouldn't it be great if we could vaccinate against these allergens and particles? Allergen-specific immunotherapy has shown to relieve symptoms and is the only treatment inducing a long-lasting protection by induction of protective immune responses. The following study produce an allergy vaccine designed to reduced anaphylactic properties with the combined features of attenuated T cell activation, retained molecular integrity and induction of efficient IgE blocking IgG antibodies to cats. This study may lead the way in producing allergy vaccines to safely and effectively treat patients.

Cat allergens are generated when cats lick and groom themselves. The saliva dries and small particles become airborne. More than 95% of patients suffering from cat allergies show a reaction to major allergen, Fel d 1. The following steps were used to generate mutant proteins of Fel d 1 then IgE binding capacity were analyzed:

1. Error-prone PCR (epPCR) was done on the Fel D 1 to generate mutants that retained epitope function were then expressed in E. Coli.

2. The proteins were then extracted and eluted by size exclusion chromatography, 30 kDa, similar to Fel D 1 wild type.


The IgE binding capacity and T cell activations were then analyzed and showed that these mutants actually reduced IgE binding affinity and reduced T cell activation. This method can definitely serve as a means of generating vaccines for the various types of allergens.


Source:

In vitro evolution of allergy vaccine candidates, with maintained structure, but reduced B cell and T cell activation capacity.

Nilsson OB, Adedoyin J, Rhyner C, Neimert-Andersson T, Grundström J, Berndt KD, Crameri R, Grönlund H.

PLoS One. 2011;6(9):e24558. Epub 2011 Sep 13.

PMID:

21931754