...

Multiple cells can have the same clonotype and each clonotype can have multiple makeups. Each clonotype contains one or more chains (TRA and TRB for T cells and IGH, IGK and IGL for B cells), the highest scoring V, D, and J gene segments, and CDR3 nucleotide sequence. T cells have a TRA and TRB chain with V, D, J and C regions.  In B cells, IGH is the heavy chain which has a V, D, and J region while IGK and IGL are the light chains with a V and J region. The Immunoglobulins have two identical heavy chains and two identical light chains. B cell isotypes are antigenic determinants that characterize the classes and subclasses of heavy chains and types and subtypes of light chains; the constant region (C gene) produced by the B cell changes but the V regions and specificity do not.  Constant regions do not participate in antigen recognition, instead C regions interact to mediate biological function; so isotypes have different function but can bind the same antigen. 

References

Tonegawa 1983.  https://www.nature.com/articles/302575a0