Question: Gamma-delta T Cells Are Weird. (Yes, That Capitalization Is Intentional.) Although They Undergo V(D)J Recombination To Produce Their  Chains, They Have A Limited Repertoire Of Gene Segments To Use, And Apparently Only Certain Combinations Are Stable (for Example V9/V2), Further Limiting What Antigens They Can See. Additionally, They Do Not …

Gamma-delta T cells are Weird. (Yes, that capitalization isintentional.) Although they undergo V(D)J recombination to producetheir  chains, they have a limited repertoire of gene segments touse, and apparently only certain combinations are stable (forexample V9/V2), further limiting what antigens they can see.Additionally, they do not require seeing MHC molecules withpeptides to function, suggesting they do not always seeprotein-based antigens. Weirder yet, some  T cell subsets havethe ability to phagocytose antigen and themselves function asantigen presenting cells. Some scientists argue that these featuressuggest that  T cells are an evolutionary ‘left-over’, a bridgingcell type between ancient innate immune cell types and the morerecently developed adaptive cell types.

Identify two other pieces of evidence from the text orliterature and explain why they do or don’t support the idea that T cells are “missing links” of the immune system.

(8 points, 4 per explanation)