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Molecular and Cellular Basis of Increased Affinity in the B Cell Antibody Response

crisscrosscutout:

The defining feature of the adaptive immune response is its specificity, its unique ability to mount a precisely targeted response to just about any non-self intruder.  While both B and T cells are capable of targeting certain antigens, the B cell receptor (BCR) is virtually unlimited in its potential specificities. It can bind to every class of biological molecule and even some external, synthetic molecules (Chan and Brink, 2012). The process of refining the BCR for this purpose has been studied extensively, yet the exact mechanism remains elusive. This is due in part to the fact that the complex mutagenic pathways involved in the selection and generation of high-affinity B cells are constantly changing, making it impossible to track cells of known affinities through the cycle to their ultimate fate (Anderson et al., 2009). Despite these challenges, a proposed model describes a process in which the initial V(D)J rearrangement in naïve B cells in bone marrow is followed by subsequent rounds of somatic hypermutation (SHM) in forming the germinal centre, which allows for the accumulation of point mutations on the variable region of the BCR and is responsible for any change in receptor affinity. The finer details of BCR selection are not well understood, but it is surmised that affinity maturation relies on a two signal pathway (Victoria and Nussenzweig, 2012; Zotos and Tarlinton 2012). The first part is when SHM takes place and selection of the newly mutated BCR is antigen dependent. The second requires help from CD4+ T helper cells in the follicular zones (Tfh cells) (Chan and Brink, 2012). It is hoped that future understanding of affinity maturation can be used to help in the fields of autoimmunity, hypersensitivity and vaccine development.

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The Impact of Super Shedding on the Transmission Dynamics of Human and Animal Pathogens

crisscrosscutout:

Transmission patterns are one of the most important aspects in the epidemiological study of pathogens because understanding how a disease gets into and throughout a population can lead to more effective and streamlined responses. Differences in transmission rates can result from both intrinsic and extrinsic variation, these factors are referred to collectively as transmission heterogeneities. One such heterogeneity is super shedding, in which a small number of infected individuals shed extremely high numbers of a pathogen relative to other individuals, therefore making them responsible for the majority of the transmission burden (Chase-Topping et al., 2008). Though the phenomenon of super shedding is postulated to be important to a variety of different diseases, it has been most studied in Escherichia coli O157:H7, an important zoonotic pathogen. The hope of current research is to figure out a means of targeting control measures at super shedders or the mechanisms of super shedding to prevent transmission.

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mindblowingscience

Calling all lady scientists!

shychemist:

scientific-women:

We want to create an index of the lady scientists on Tumblr, much like shychemist did for all scientists.  (Have we thanked you lately?!)  However, it’s a bit more challenging as not all of you announce your gender on your blogs.  So, if you identify as a woman/female,* let us know if you want to be included!

*Obviously we don’t want to be exclusionary.  This is just our cause, to give women more visibility in the sciences.  I believe that seeing a great long list alone would be encouraging to any aspiring female scientist.  

Women in Science you should definitely check this blog out. Sounds like a great idea! :)

Thanks for the nod, by the way. ;)

I don’t know if I count as a scientist since I am not even yet in college (though I have done bio 1 & 2 already) but this is cool

we-are-star-stuff

Creation of a Tumblr Science Network

cryusaki:

I would like to see Science gain popularity on Tumblr and to do so I am creating a network of Blogs that will post high quality science related material for all to see. Think of this as science blogs featuring each other in one another’s page or by having a common blog as to where an interested Tumblr viewer can find us all. This will help the smaller Tumblr channels that post great material the attention they deserve. If you share this idea with me send me a message and we can get plans in order.

For now please reblog this message to get this message to all big and small Tumblr science blogs!