Production of autoantibodies by TG2-specific gut plasma cells is a hallmark of celiac disease. Previous studies have revealed biased selection of IGHV and IGKV gene segments, low number of mutations and preferential targeting of N-terminal epitopes among TG2-specific autoantibodies. Now, we produced a panel of germline and affinity matured antibodies belonging to the same clonal family and targeting the main N-terminal TG2 epitope, together with antibodies targeting non-N-terminal epitopes to analyse the effect of mutations on antibody affinity, using surface plasmon resonance technique. In addition, to get a more detailed understanding of the selection of TG2-specific B cells, we analysed the heavy and light chain CDR3 loops among plasma cells using the two most common IGHV:IGKV pairs (IGHV5-51:IGKV1-5 and IGHV5-51:IGKV1-39) by taking advantage of single-cell Ig sequencing data from 2329 TG2+ and 1398 TG2- plasma cells isolated from gut biopsies of 19 celiac disease patients. The mutations do not have a significant effect on TG2 affinity, rather the germline reverted antibody retain reduced but significant TG2 affinity, which suggests that unlike some other autoimmune diseases, anti-TG2 reactivity is not a by-product of cross-reactivity acquired by SHM. IGHV5-51:IGKV1-5 antibodies show preference for certain IGHJ and IGKJ gene segments, whereas IGHV5-51:IGKV1-39 antibodies show selection for IGHD. When we swapped the CDR-H3 loop between two antibodies using the two common V gene pairs, we observed complete loss of reactivity, suggesting its essential role in TG2 binding. From this study, it is evident that preference for certain HV:KV pairing cannot be explained by an inherent ability to bind TG2 without the involvement of CDR-H3 loop. Effect of mutations on antibody affinity for TG2 do not dependent on targeting TG2 domain; rather it varies on TG2-specific antibodies.