A coded study of antitumor immunity to human lung cancer assayed by tube leukocyte adherence inhibition.

The present study was undertaken to evaluate the specificity of antitumor immunity to human lung cancer, measured by an in vitro assay--tube leukocyte adherence inhibition (LAI). We standardized and monitored the putative tumor antigen activity of the extracts by testing leukocytes from controls and patients with lung cancer in the Montreal General Hospital. A specific antitumor response to a lung cancer antigen was detected with coded leukocytes from 56% (20 out of 36) of patients with epidermoid lung cancer. By contrast, 4% (2 out of 53) of patients with inflammatory lung disease and none of 46 other patients with cancer metastatic to the lung or with other diagnoses had an LAI-positive result. The LAI response was inversely related to the extent of cancer: 80% (8 of 10) with Stage I, 66% (2 of 3) with Stage II, 54% (6 of 11) with localized Stage III, and 33% (4 of 12) with widespread Stage III were LAI positive. Leukocytes from patients with epidermoid, adenocarcinoma, or small cell lung cancer reacted to a common tumor antigen shared by extracts of epidermoid and small cell lung cancer. This study with coded samples from a remote hospital confirms the results of other investigators that the LAI measures an antitumor immune response to human organ-specific neoantigens.

A computerized tube leukocyte adherence inhibition assay to detect antitumor immunity in early human cancer: a review of two years' experience.

A 2-year experience with a computerized in vitro assay of leukocyte adherence inhibition (LAI) indicated that patients with cancer of either the colorectum, stomach, pancreas, breast, or lung expressed antitumor immunity to an organ-type specific neoantigen. About 1% of the 1,299 control subjects with benign or malignant disease had a positive LAI assay and 2.5% of patients with inflammatory disease of the colorectum, stomach, pancreas, or lung had a positive LAI assay when tested against tumor extracts of the same organ. Of the 351 patients with cancer of either the colorectum (111), stomach (40), pancreas (28), lung (57), or breast (116) who harbored a microfocus of cancer, 80% or more were LAI positive. As the stage of the cancer advanced, fewer patients were LAI positive. Nine of 45 patients (20%) with colon adenomas had a positive LAI response to colon cancer antigen and 17 of 204 patients (8%) with benign breast disease reacted to the breast cancer antigen. Our results suggested that the leukocytes of some of the LAI-positive patients with either colon adenomas or benign breast disease were responding to an organ-specific neoantigen. Whether the acquisition of a cell surface tumor antigen by the colon adenomas and the dysplastic lesions of the breast implies an irretrievable step to ultimate malignancy is unknown. Most patients exhibit a vigorous antitumor immune response when the cancer exists as a microfocus, and some even before the neoplasm has acquired the capacity to invade.

Partial purification of organ-specific neoantigens from human colon and breast cancer by affinity chromatography with human tumour-specific gamma-globulin.

Organ-specific neoantigens (TA) shed from the tumours of patients with metastatic breast or colon cancer and which had filtered into the urine were partially purified by a combination of physicochemical methods and affinity chromatography. TA activity of the isolated materials was monitored by the blocking Tube LAI assay. Urinary protein was precipitated by 80% saturated ammonium sulphate. Albumin was removed by affinity chromatography with blue Sepharose CL-6B. Affinity columns of human IgG were prepared from sera of patients whose leucocytes were LAI+ to the breast- or colon-cancer extracts. The anti-breast-TA affinity column bound the TA in the urine of patients with metastatic breast cancer but not that of patients with metastatic colon cancer. The TA in urine of patients with metastatic colon cancer was bound by the anti-colon-TA affinity column. Analysis by SDS PAGE revealed that the isolates with and without TA activity were composed mostly of urinary protein which had bound nonspecifically to the human IgG affinity columns. With an affinity column of anti-NHS and Protein A, some of the contaminants were removed, to reveal SDD PAGE unique bands at about 38,000 and 12,000 mol. wt in the isolate with breast-TA activity. Rabbit antisera, raised to the material that had bound nonspecically to the anti-breast-TA affinity column, were used as an anti-nonspecific affinity column to remove the contaminants in the isolates from the affinity columns of anti-breast TA and anti-colon TA. After passage through the anti-nonspecific affinity column, the material that contained the putative breast or colon cancer TA revealed a unique band at about 38,000-40,000 mol. wt and residual fine bands at about 25,000-30,000 mol. wt. Both the control material and material with TA activity had similar bands at about 25,000 and 50,000 mol. wt. The specific activity of the putative colon or breast TAs, as measured by the blocking Tube LAI assay, was increased from about 30 to 5000-10,000 u/mg, a 125-400-fold enrichment.

Tube leukocyte adherence inhibition (LAI) assay in gastrointestinal (GIT) cancer.

Tumor-specific immunity to carcinoma of the colon, pancreas and stomach was assayed by tube LAI. Cancers of the colon, pancreas and stomach, were shown to possess organ-type specific neoantigens. In 115 patients with colon cancer, 100%, 75%, 61% with Dukes' A, B and C cancer were LAI positive, respectively. Even a microfocus of in situ cancer in a colon adenoma was sufficient to stimulate measurable tumor-specific immunity in the host. In Dukes' D cancer, 25% of patients with widespread metastasis were positive, whereas 100% with solitary lesions were positive. Reactive leukocytes from patients with colon cancer did not react to extracts of normal bowel mucosa or villous adenoma from LAI-negative patients. Leukocytes from 19% (3 of 16) of patients with colon adenomas reacted to the extract of colon cancer but not normal colon mucosa. Moreover, the LAI-positive response of the patients with colon adenomas or colon cancer is directed to a colon cancer TSA which is linked to beta2-microglobulin. These studies suggest that some colon adenomas express TSA before morphological evidence of cancer. It is not known if the acquisition of a cell surface TSA is an irreversible step toward unrestrained growth and metastasis. In pancreatic cancer, 100% of patients with cancers less than 5 cm and without metastasis were LAI positive, whereas 29% were positive when the cancer was greater than 5 cm or had metastasized. In Patients with stomach cancer, 100% with Stage II and 46% with Stage III and IV cancer were LAI-positive. Leukocytes from patients with other GIT cancers and from patients with inflammatory bowel disease or pancreatitis did not react with extracts of colon, stomach or pancreatic cancer. Leukocytes from patients with metastatic cancer, usually did not react in the tube LAI assay because their surfaces were coated in vivo with TSA. LAI reactivity was present when CEA was not detectable and when CEA levels were elevated LAI activity was often absent. The present study suggests that the automated tube LAI shows sufficient promise to warrant studies to determine its efficacy for the diagnosis of GIT cancers.

Leucocyte adherence inhibition for detecting specific tumour immunity in early pancreatic cancer.

Tumour-specific immunity to pancreatic tumour antigens, assayed by an automated tube leucocyte-adherence inhibition assay (L.A.I.), was detected in 3 of 3 patients with localised pancreatic cancer and 3 of 8 patients with more extensive pancreatic cancer. Leucocytes from pancreatic cancer patients with L.A.I. reactivity did not react to antigens of stomach, colon, or lung tumours; leucocytes from patients with stomach, colon, or lung cancer of inflammatory disease of the pancreas and bowel did not show L.A.I. reactivity to pancreatic tumour antigens.