Is this a good answer? Would you add anything to this answer?Thank you.

5) Gamma-delta T cells are Weird. (Yes, that capitalization isintentional.) Although they undergo V(D)J recombination to producetheir γδ chains, they have a limited repertoire of gene segments touse, and apparently only certain combinations are stable (forexample Vγ9/Vδ2), 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 γδ T cell subsets havethe ability to phagocytose antigen and themselves function asantigen-presenting cells. Some scientists argue that these featuressuggest that γδ 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 thatγδ T cells are “missing links” of the immunesystem.

(8 points, 4 per explanation)

Answer:

Gamma delta T cells (γδ T cells) are T cells with a specializedT-cell receptor (TCR) on their outer covering or surface.Comparisons between the δ and γ V, D and J gene portions within theprimate species have shown a fascinating order of how these locihave evolved (Holtmeier & Kabelitz, 2005). The gene segments ofthe δ locus have not changed considerably in the primate ancestryfrom humans to marmosets; the gene directive, overall, iswell-looked-after and most of the genes remain purposeful with fewduplications or deletions.

Evolutionary perspectives of the Gamma delta Tcells:

Gamma delta T cells are an enigma of the immune system. Theirtriggers are not really understood. An attempt to explain theirrole as the cells that bridge the gap between innate and adaptiveimmunity doesn’t really justify their niche in the immune system,rather it focuses on their complex behavior. Therefore, hypothesescan be derived from the inferences that are made as a bid toexplain their fundamental behaviors, as follows:

First Hypothesis:

The gamma delta T cells are placed at the borderline between theinnate immune response that is quick in its action against anyagents whether it be pathogens or micro-organisms, coming fromoutside, and the adaptive immune response which is extremelyspecific in its action and uses the B and T cells to tailor animmune response for the body, against the incoming foreign agents.This is basically because of the uniqueness of the gamma delta tcells which bear TCRs, that are mostly invariant in nature. A goodexample in this regard would be the Natural Killer T cells thatbear the CD1d-restricted sites (Holtmeier and Kabelitz, 2005). Thishypothesis says that gamma delta t cells are indeed, the missinglinks between the two evolutionary types of immunity.

Second Hypothesis

The second hypothesis is a reinforcement of the fact that gammadelta T cells really are the missing links between the evolutionarysteps of immunity. Some evidence has surfaced in the recentfindings that confirm recent work has shown that Vγ9/Vδ2 T cells inhuman are also proficient enough to carry out complex processessuch as the phagocytosis, a function previously found to occur onlyin innate myeloid lineage cells such as neutrophils, monocytes anddendritic cells (Holtmeier and Kabelitz, 2005). This makes the factvery credible that these cells are actually the link between thetwo types after all.