Comparison by leukocyte adherence inhibition of human immune response to cancer-associated immunogens, Thomsen-Friedenreich (T) and Tn, myelin basic protein, and organ-specific cancer neoantigens

Cancer vaccines and carbohydrate epitopes

Tumor-associated carbohydrate antigens (TACA) result from the aberrant glycosylation that is seen with transformation to a tumor cell. The carbohydrate antigens that have been found to be tumor-associated include the mucin related Tn, Sialyl Tn, and Thomsen-Friedenreich antigens, the blood group Lewis related Lewis(Y), Sialyl Lewis(X) and Sialyl Lewis(A), and Lewis(X) (also known as stage-specific embryonic antigen-1, SSEA-1), the glycosphingolipids Globo H and stage-specific embryonic antigen-3 (SSEA-3), the sialic acid containing glycosphingolipids, the gangliosides GD2, GD3, GM2, fucosyl GM1, and Neu5GcGM3, and polysialic acid. Recent developments have furthered our understanding of the T-independent type II response that is seen in response to carbohydrate antigens. The selection of a vaccine target antigen is based on not only the presence of the antigen in a variety of tumor tissues but also on the role this antigen plays in tumor growth and metastasis. These roles for TACAs are being elucidated. Newly acquired knowledge in understanding the T-independent immune response and in understanding the key roles that carbohydrates play in metastasis are being applied in attempts to develop an effective vaccine response to TACAs. The role of each of the above mentioned carbohydrate antigens in cancer growth and metastasis and vaccine attempts using these antigens will be described.

Anti-Thomsen-Friedenreich (T) antibody-based ELISA and its application to human breast carcinoma detection

An anti-Thomsen-Friedenreich (T) antibody-based enzyme-linked immunosorbent assay (ELISA) with high efficacy in human breast carcinoma detection is described. Immunoreactive T epitopes occur in approximately 90% of all carcinomata; all humans have anti-T antibodies, naturally occurring anti-carcinoma antibodies, induced by their own intestinal flora. Carcinoma patients, but not control subjects, show alterations of serum anti-T hemagglutinin levels. Human anti-T antibodies are predominantly IgM. In the protocol presented here, anti-T IgM antibodies are quantitated by ELISA using Immulon 2 wells coated with human blood group O erythrocyte-derived T antigen as solid phase; in addition, total IgM in each serum is quantitated by ELISA in parallel with the anti-T IgM. Inter-assay coefficient of variation was 2% for both ELISAs. Although anti-T IgM values alone distinguish between carcinoma patients and control subjects, use of the quotient, QMe, which also considers total IgM, increases this distinction. For a given serum, QMe was obtained by the formula: QMe = (100 x (anti-T IgM)2/total IgM). Sera of 242 subjects, 117 breast carcinoma patients, 36 benign breast disease patients and 89 healthy persons were analyzed. QMe identified 88% of the breast carcinoma patients: it all six (100%) in situ, 11/13 (85%) Stage I, 48/58 (83%) Stage II and III and 38/40 (95%) Stage IV patients. Sera from 83% of the 36 benign breast disease patients were negative, i.e. within normal range; five of the six positive sera originated from patients with increased long-term risk of breast carcinoma, while sera from 11 other patients with increased carcinoma risk were negative. Overall, 90% of the 125 non-carcinoma control subjects were negative by both anti-T IgM and QMe. In preliminary studies, the ELISA protocol detected 11/14 (79%) patients with carcinomata other than those of the breast. The identification of all six in situ breast carcinoma patients by QMe points to its usefulness in carcinoma detection, especially early.

Leukocyte Adherence Inhibition Test: Cell-Mediated Reactivity to Tumor Antigens in Colorectal and Lung Tumor Long Survivors

Cell-mediated Immunity versus tumor antigens (cytosols) of the same histotype and site was evaluated by means of the leukocyte adherence Inhibition (LAI) test in 44 colorectal adenocarcinoma and 17 lung squamous-cell carcinoma patients 3–10 years after surgical resection. LAI-positivity was observed in 17/44 (38.6 %) and 13/17 (76.5 %) patients, respectively, together with serum blocking factors in 7/17 (41.2%) compared to 0/13. These results indicate that a high percentage of long survivors retain an immunologic memory of the tumor antigen to which they have been exposed. The prognostic significance of serum blocking factors is less clear.