 Normally, these APC 'present' class II receptor/antigens to a great many T-cells, each with unique T-cell receptor (TCR) variants.A few TCR variants that recognize these DQ/antigen complexes are on CD4 positive (CD4+) T-cells.These T-cells, called T-helper cells, can promote the amplification of B-cells which, in turn recognize a different portion of the same antigen.