Probing method for identifying antibodies specific for selected antigens

A process for finding at least one murine VH-encoding polynucleotide encoding at least the heavy chain variable region (VH) of an antibody having binding specificity for TAG-72, the VH-encoding segment of said VH-encoding polynucleotide having a nucleotide sequence which is at least 80% homologous to the nucleotide sequence of the VHαTAG germline gene (SEQ ID NO:1), and said VH-encoding polynucleotide being a productively rearranged or mutated productively rearranged variant of the VHαTAG germline gene, said process comprising the steps of:

• A. providing at least one test medium containing at least one murine anti-TAG-72 VH-encoding polynucleotide that is a productively rearranged or mutated productive rearranged variant of the VHαTAG germline gene (SEQ ID NO:1), said VH-encoding polynucleotide comprising at least one 5′-nontranslated region (5′-NTR) of a murine anti-TAG-72 VH-encoding gene that is a productively rearranged or mutated productively rearranged variant of the VHαTAG germline gene (SEQ ID NO:1);
• B. providing at least one detectably labeled hybridization probe comprising a base sequence of, or fully complementary to, about 15 nucleotides or more of
• (1) the 5′-NTR of mRNA transcribed from the DNA VHαTAG germline gene (SEQ ID NO:1), or of DNA corresponding thereto, or
• (2) the 5′-NTR of mRNA transcribed from a productively rearranged or mutated productively rearranged variant of the DNA VHαTAG germline gene, or of DNA corresponding thereto;
• C. contacting said VH-encoding polynucleotide(s) with said probe(s) under conditions in which said base sequence of the probe(s) binds specifically to said 5′-NTR(s) of said VH-encoding polynucleotide(s) in the test medium so as to form at least one detectably labeled probe-VH-encoding polynucleotide hybrid, wherein said hybrid contains a polyntcleotide that has a nucleotide sequence that is at least 80% homologous to the nucleotide sequence of the VHαTAG germline gene and that encodes a VH that is able to function as the VH of an antibody having binding specificity for TAG-72;
• D. detecting said hybrid(s);
• and
• E. optionally isolating said hybrid(s);
• provided that, where both the VH-encoding polynucleotide and the probe are single stranded, one of these is a (+) strand and the other is a (−) strand.