Identification of a Human Cancer Related Organ-Specific Neoantigen

Human cancers express organ-specific neoantigens (OSNs) which elicit specific cellular immune responses in the cancer patient, as demonstrated by leukocyte adherence inhibition (LAI), an in vitro immune response assay. A purified protein of MW 40,000 (p40) exhibiting OSN (colon specific) activity was cleaved into specific peptide fragments and their partial amino acid sequences determined. This information was used in the polymerase chain reaction (PCR) to obtain a 992 bp cDNA clone (PCR-992) from a human colon adenocarcinoma cell line (LS-180). By comparison of the predicted amino acid sequence of PCR-992 with the known sequence of p40 peptides, PCR-992 was shown to correspond to almost the entire coding region of p40. Nucleotide sequence analysis suggested that the protein was mycoplasmal in origin due to its high A+T content (76%) and the presence of five in frame TGA termination codons; at least two of the latter are actually read as tryptophan, a known feature of mycoplasma translation. We have confirmed this origin by direct isolation of a contaminating mycoplasma species from the LS-180 cell line and demonstration that it could be hybridized with the PCR-992 probe. Northern and PCR analysis of RNA preparations from the contaminated LS-180 cell line showed that p40 was part of the high affinity transport system operon of Mycoplasma hyorhinis (Dudler et al, EMBO J., 7: 3963-3970, 1988). Total protein lysates of Mycoplasma hyorhinis cultivated without animal cells could elicit positive LAI responses when incubated with cancer patient leukocytes but not with normal patient leukocytes. The organ-specific nature of the response was, however, not observed indicating that host cell-mycoplasmal interactions may play a role in determining the organ-specific nature of p40 seen with the LAI. The significance of these findings will be discussed in the context of previous thinking regarding the origin of OSNs.     

Leukocyte migration inhibition and leukocyte adherence inhibition (LMI- and LAI-assay) in cancer patients by using preparations from human fetuses]

The sensitization of lymphocytes from patients with different tumors was tested against a 3 M KCl-extract of fetal tissue (3.--6. month) by the leukocyte adherence inhibition assay (LAI) and by the leukocyte migration inhibition assay (LMI). Sensitization was compared with the reactivity of controls without any detectable tumor. In the LAI assay the leukocytes of 13/15 patients and 2/12 controls showed an inhibition of the adherence. In the LMI-assay 11/17 tumor-bearing patients and 6/18 controls reacted positive in the presence of the antigen preparation. The two methods demonstrated that patients bearing tumors of different histology are sensitized to fetal antigens.     

Transmembrane signal defect and absence of cancer extract induced leukocyte adherence inhibition (LAI) for leukocytes from patients with advanced cancer

Summary Leukocytes from patients with early cancer exhibit leukocyte adherence inhibition (LAI) when incubated with extracts of cancer of the same organ and histogenesis, whereas leukocytes from patients with advanced cancer seldom do. To understand the reason for this refractory state, tumor antigen-induced LAI and transmembrane signalling were measured in the same leukocytes. Transmembrane signalling was measured by changes in membrane potential () by the [³H]tetraphenylphosphonium equilibration technique. When leukocytes from patients with early breast cancer were incubated with extracts of breast cancer and malignant melanoma they showed changes consisting of depolarization and hyperpolarization beginning within 0.5 min after addition of the breast cancer extract and finishing 15 min later. Moreover, they showed no changes when incubated with extracts of normal breast tissue. Leukocytes from subjects without cancer seldom showed changes. In criss-cross experiments, leukocytes from patients with melanoma only exhibited changes when incubated with the melanoma extract. There was a strong correlation between cancer extract-induced change and LAI. The change was triggered by leukotriene-like mediators from antibody-dependent monocytes. Authentic leukotrienes triggered changes in all subpopulation of leukocytes. Leukocytes from patients with advanced breast cancer when incubated with breast cancer extract did not transmit a signal or show LAI. Brief elevation of intracellular cyclic AMP restored both change and LAI induced by breast cancer extracts, indicating that reactive leukocytes are present but in a refractory state. We conclude that leukocytes from patients with advanced cancer do not react in LAI because tumor antigen does not trigger a transmembrane signal to initiate the cascade of biochemical reactions and physiological changes for LAI.Abbreviations CCCP carbonyl cyanide m-chlorophenylhydrazone - cyclic AMP cyclic adenosine monophosphate - ETYA eicosatetraynoic acid - HEPES 4-(2-hydroxyethyl)-1-piperazine ethansulfonate - LAI leukocyte adherence inhibition - NAI nonadherence index - OSN organ-specific cancer neoantigen - PBL peripheral blood leukocytes - PGE₂ prostaglandin E₂ - [³H]TPP⁺ [phenyl³H]tetraphenylphosphonium bromide - transmembrane potential     

Fetal growth in the baboon during the second half of pregnancy

The normal growth profile of critical fetal organs through the last third of gestation has not been documented in detail in human fetuses or the fetus of any nonhuman primate species. Recent epidemiological studies in human pregnancy suggest that fetal growth plays a major role in the programming of life-long health by modifying cardiovascular, pancreatic, brain, and liver growth. The present study aimed to produce a detailed database of individual organ growth in the fetal baboon in late gestation. Fetal organ weights were obtained from 43 baboon fetuses between 121 and 177 days of gestation. Various organs (brain, heart, kidney, femur, intestines, and spinal cord) showed no sign of slowed growth in late gestation while growth of others (lung, liver, stomach, and bladder) accelerated in late gestation. The fetal adrenal and thymus showed a decrease in growth rate over the final 20 and 10 days of gestation respectively. These observations provide a database that will permit analysis of factors responsible for regulation of normal and altered fetal organ development in this important experimental species.     

Transfer factor in vitro abrogation of blocking factors and amplification of immunoreactivity directed to soluble tumor associated antigens in the leukocyte adherence inhibition assay

Summary 26 breast cancer patients with recurrent disease were studied in order to evaluate whether transfer factor (TF) could abrogate serum blocking factors (SBF) and transfer or amplify immune reactivity directed to tumor-associated antigens (TAA) by using the leukocyte adherence inhibition assay (LAI). When 11 leukocyte samples obtained from patients reactive to cancer extract were preincubated with autologous blocking sera in the presence of PBS, nonspecific TF, or specific TF, leukocytes from these patients gained reactivity against breast cancer extract in none out of 11, one out of 11, and nine out of 11 experiments, respectively. Specific TF was obtained from donors with positive LAI breast cancer extract. Mean percentage LAI differences between control extract and breast cancer extract were –4.5±2.6, 0.5±1.7, and 15.5±2.4. The results of specific TF were significantly different from those of nonspecific TF (P<0.005).When nine leukocyte samples obtained from patients unreactive to cancer extract were preincubated with autologous blocking sera in the presence of PBS, nonspecific TF, or specific TF, leukocytes from these patients gained reactivity against breast cancer extract in none out of nine, one out of nine, and seven out of nine experiments, respectively. Mean percentage LAI differences between control extract and breast cancer extract were –4.6±2.0, 0.6±2.3, and 11.8±3.5. The results of specific TF were again significantly different from those of nonspecific TF (P<0.005).When allogeneic blocking sera were utilized, similar results were obtained. When specific TF was administered in two doses, 1 week apart subcutaneously to six breast cancer patients who were unreactive to breast cancer extracts, four patients gained reactivity against breast cancer extracts.Our in vitro experiments support the presence of a specific component in transfer factor extract which can transfer or amplify cell-mediated reactivity with abrogation of SBF directed at TAA.Abbreviations BSS = Balanced Salt Solution - LAI = Leukocyte Adherence Inhibition - PBS = Phosphate Buffered Saline - RPMI = Roswell Park Memorial Institute - SBF = Serum Blocking Factors - TAA = Tumor Associated Antigen - TF = Transfer Factor     

Cross-reactivity of lung cancer patients' leucocytes in the leucocyte migration inhibition test

Summary Panels of 3 M KCl extracts of squamous-cell carcinomas, adenocarcinomas and oat-cell carcinomas of the lung were used for a comprehensive analysis of cross-reactivity in the leucocyte migration test. Lung cancer patients' leucocytes showed positive reactivity in 69%–100% of cases (n=353). No significant differences were observed when data were grouped with respect to the histological type of the tumours used for extraction or of the tumours of the leukocyte donors. Leukocytes of patients bearing tumours of nonpulmonary origin exposed to lung cancer extract panels and leukocytes of lung cancer patients exposed to gastrointestinal cancer extract panels were definitely less reactive (35%–47% and 6%–38%, respectively). However, a high reaction frequency was found in patients with lung metastases from different nonpulmonary tumours. This group of patients also frequently showed reactivity (52%) with normal lung tissue extracts. Patients with benign lung diseases reacted positively with lung tumour extracts in 25%–39% of cases, but donors with other benign disease and healthy controls were virtually nonreactive (0–14%).Hence, a high degree of cross-reactivity occurs in the lung cancer system and restricted cross-reactivity occurs with tumours of other organs. Possible explanations for the lung-oriented reactivity of patients with lung metastases are discussed.Abbreviations LMI leucocyte migration inhibition - MI migration index - LMT leucocyte migration test - SCC squamous-cell carcinoma - OCC oat-cell carcinoma - AC adenocarcinoma     

Conversion of human lymphocytes to antitumor immune reactivity by xenogeneic and allogeneic imune RNA detected by leukocyte-adherence inhibition tests

Summary Using leukocyte adherence inhibition (LAI) tests, we studied the activity of xenogeneic immune RNA (I-RNA) extracted from the spleen and lymph nodes of sheep after immunization with human breast carcinoma tissue or keyhole limpet hemocyanin (KLH) in inducing lymphocytes from normal healthy donors to mediate immune responses in vitro. Mononuclear cells isolated from venous blood of normal donors, depleted of monocytes and, in some experiments, separated into T cells and non-T cells, were incubated with and without anti-breast carcinoma I-RNA or anti-KLH I-RNA for 20 min at 37° C. Then, lymphocyte adherence was determined by a Coulter counter method in the presence of 3 M KCl extracts of breast carcinoma tissues, control tissue, or KLH. Following incubation with anti-breast carcinoma I-RNA, the adherence of lymphocytes from normal donors was found to be inhibited only in the presence of breast carcinoma extracts. Following incubation with anti-KLH I-RNA, lymphocyte adherence was inhibited only in the presence of KLH. The principal effector cells involved appeared to be T lymphocytes. I-RNA treatment with RNase, but not with DNase or pronase, completely abrogated the LAI responses. In a blind study utilizing coded samples of xenogeneic and allogeneic I-RNA of unknown origin, samples containing activity against breast cancer extracts were identified correctly by LAI. Abbreviations used: I-RNA, immune RNA; LAI, leukocyte adherence inhibition; KLH, Keyhole limpet hemocyanin; PBS, phosphate buffered saline; RNase, ribonuclease; DNase, deoxyribonuclease     

Inhibition of tumor growth in vitro by the extract of fagopyrum cymosum (fago-c)

Fagopyrum cymosum (Trev.) Meisn has long been used in China to treat various ailments of the lung, including lung tumors. This study investigated whether Fagopyrum cymosum extract (Fago-c) has effects on other organs. Human cancer cells derived from 10 different organs were employed, and their growths as affected by Fago-c were investigated. It was found that the growth of cancer cells from lung, liver, colon, leukocytes and bone is inhibited by Fago-c. However, cancer cells derived from prostate, cervix, ovary and brain are not sensitive to Fago-c, and the extract stimulates the growth of cancer cells from breast (MCF-7). Synergistic inhibition effect of Fago-c and daunomycin was observed in human lung cancer cells (H460). Cellular proteins from H460 cells treated with Fago-c were analyzed by 2D-gel electrophoresis. A protein (M.W./pI = 20K/5.9) was induced. The Fago-c extract was analyzed by High Performance Liquid Chromatography (HPLC). Four major and twenty minor components were identified. These studies indicate that the effect of Fago-c in inhibiting the growth of cell lines derived from certain organs.     

Amplification of lymph node cell tube leukocyte adherence inhibition (LAI) reactivity by leukocyte adherence inhibition factor (LAIF)

This investigation examines the immunologic basis for specific antigen-induced tube leukocyte adherence inhibition (LAI) reactivity of draining lymph node cells (LNC) from dogs with canine transmissible venereal sarcoma (CTVS). CTVS regressor LNC, macrophage-depleted LNC, and enriched T lymphocyte fractions, but not enriched B lymphocyte fractions, were specifically reactive to CTVS antigen extract in direct tube LAI. In addition, regressor LNC amplified tube LAI responses by generating supernatants with leukocyte adherence inhibition factor (LAIF) activity for normal dog indicator LNC and enriched peripheral blood mononuclear cells (PBMC) in an indirect tube LAI assay. However, macrophage-depleted LNC and enriched T lymphocyte fractions failed to generate supernatants with LAIF activity, suggesting that macrophage accessory cells play a central role in the amplification of tube LAI. Interestingly, CTVS regressor peripheral blood leukocytes (PBL) and PBMC, which were specifically reactive in direct tube LAI, also failed to generate supernatants with LAIF activity. These findings demonstrate a distinction between LAIF-mediated amplification and direct tube LAI reactivity, and suggest that leukocyte populations with differing cellular proportions and from different immunologic compartments may participate in tube LAI via different mechanisms.     

EFFECTS OF SINUSOIDAL MAGNETIC FIELD ON ADHERENCE INHIBITION OF LEUKOCYTES

Response of leukocytes to exposure to an external magnetic field with frequency 50 Hz and sinusoidal waveform was investigated in vitro using the leukocyte adherence inhibition (LAI) assay developed as a measure of cell-mediated immunity. Leukocytes taken from healthy humans adhere, but their adherence decreases after 1 hr of exposure to the magnetic field with magnetic induction of 1 and 10 mT. The majority of leukocytes taken from cancer patients before any medical treatment do not adhere, and exposure to the magnetic field increases adherence. Correlation between the LAI assay results and the cell-mediated immunity suggests an effect of magnetic fields on leukocyte immune function in humans.     

Reaction of the leukocytes of melanoma patients and control donors,including pregnant women,with melanoma- and fetus-derived materials

Summary Using a one-stage capillary leukocyte migration inhibition assay, we examined peripheral blood leukocytes from 97 patients with malignant melanoma, 194 pregnant women, and 123 non-pregnant donors for their reactivity with materials from fetal and melanomatous tissues. As in previous studies, we found melanoma extracts selectively to inhibit melanoma patients' leukocytes. First-trimester fetal extracts also selectively inhibited melanoma patients' leukocytes, suggesting their cross-reactivity with melanoma-derived antigens. We could not localize the source of the inhibitory materials within the fetuses. We found no evidence that pregnant women were selectively immunized to fetal or melanoma extracts, regardless of their parity or the stage of their pregnancy.     

Study of fetal organ growth in Wistar rats from day 17 to 21

A total of 1633 Wistar rat fetuses was used to determine weights of the fetus and several fetal organs on days 17 to 21 of gestation. Heart, lung, liver, kidney, stomach, intestine, brain, femur, thyroid and adrenal weights were recorded. Growth curves of the whole body and organs were calculated. A linear semi-log relationship between organ weight and day of gestation was shown. The doubling weight times were 1.5 days for whole bodies and for organs they ranged between 0.9 (spleen) and 3.4 (adrenals) days. A correlation between the rate of organ growth and the start of the organ function was observed.     

Regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with progressing or spontaneously regressing canine transmissible venereal sarcoma (CTVS)

Summary We examined the regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with regressing or progressing canine transmissible venereal sarcomas (CTVS). Both regressor and progressor peripheral blood leukocytes (PBL), draining and nondraining lymph node cells (LNC), and splenic leukocytes were significantly responsive to CTVS antigen extract in tube LAI. In contrast, a significant decrease in basal glass adherence of progressor PBL, draining and nondraining LNC, and splenic leukocytes was observed. Normal glass adherence was restored to progressor leukocytes by extensive washing with warm serum-free media, while significant tube LAI responsiveness to CTVS antigen extract was maintained. Preincubation of regressor PBL and LNC with progressor sera in two-stage tube LAI decreased the basal glass adherence of treated leukocytes. This effect of progressor sera was heat labile, a characteristic of CTVS antigen. Collectively, these findings suggest that progessor leukocytes and progressor sera treated regressor leukocytes were activated by interaction with serum CTVS antigen and thus behaved in tube LAI as stimulated cells, even in the absence of CTVS antigen. Regressor but not progressor sera were shown to contain anti-CTVS IgG with specific arming activity for normal dog PBL, but not LNC in two-stage tube LAI. The nonadherent response of peripheral blood neutrophils in two-stage tube LAI was proportional to the concentration of arming IgG, whereas no change was observed in glass adherence of PBL. The results of this study define the role of progressor and regressor serum factors in the mechanism of tube LAI and demonstrate a relationship between leukocyte glass adherence and the clinical course of CTVS. These findings show that tube LAI is a simple and reproducible measure of active factors in the immune response to a tumor.This investigation was supported in part by grant, CA-23469, from the National Cancer Institute, DHHS, and is submitted as Scientific Contribution No. 1051, Storrs Agricultural Experiment Station, University of Connecticut, Storrs, CT 06268 USA     

Alterations in the expression of homing-associated molecules at the maternal/fetal interface during the course of pregnancy.

One of the most fascinating immunologic questions is how the genetically distinct fetus is able to survive and develop within the mother without provoking an immune rejection response. The pregnant uterus undergoes rapid morphological and functional changes, and these changes may influence the nature of local immune responses at the maternal/fetal interface at different stages of gestation. We hypothesized that specialized mechanisms exist to control access of maternal leukocyte subsets to the decidua and that these mechanisms are modulated during the course of pregnancy. At the critical period of initial placenta development, the maternal/fetal interface displays an unparalleled compartmentalization of microenvironmental domains associated with highly differentiated vessels expressing vascular addressins in nonoverlapping patterns and with recruitment of specialized leukocyte subsets (monocytes, granulated metrial gland cells, and granulocytes) thought to support, modulate, and regulate trophoblast invasion. One of the most striking observations at this time of gestation is the almost complete exclusion of lymphocytes from the maternal/fetal interface. The second half of pregnancy is characterized by a partial loss of microenvironmental specialization and different switches in vascular specificity within the decidua basalis, paralleling dramatic changes in the populations of recruited leukocytes (e.g., a striking influx of lymphocytes, especially T cells). In the term pregnant uterus, the expression of all vascular addressins decreased dramatically; only weakly staining maternal vascular segments remained. These segments may define sites of extremely low residual traffic in the term decidua, which contains remarkably few maternal leukocytes overall. Our results suggest that the maternal/fetal interface represents a situation in which leukocyte trafficking is exquisitely regulated to allow entry of specialized leukocyte subsets that may play a fundamental role in immune regulation during pregnancy.     

Serodiagnosis of cancers by ELISA of anti-histone H2B antibody

An enzyme-linked immunosorbent assay method for serodiagnosis of cancers was developed by employing histone H2B. This method measures anti-histone H2B antibody levels in sera and includes a device for coating the plastic immunoplate with a mixture of histone H2B and diluted fetal calf serum. The coating of immunoplates with this mixture decreased apparent sensitivity of the assay compared with that in the absence of fetal calf serum, but effective reduction of nonspecific background enabled a specific assay of anti-histone H2B antibody with excellent reproducibility. By this method cancer patients were discriminated from normal healthy subjects at detection rates of 37% for lung cancer, 33% for liver cancer, 50% for pancreatic cancer, 42% for colon cancer, and 78% for cervical cancer. However, stomach and esophagus cancers showed detection rates of less than 17%, which are comparable to the values for benign diseases. It is likely that this assay method detects squamous cell carcinomas at relatively high rates.     

Colorectal cancer diagnosis by a direct leukocyte migration test using a panel of tumour extracts

Summary In a direct leukocyte migration test, peripheral blood leukocytes were pulsed with a high dose (2.5 and 0.5 mg/ml) of 3 M KCl extracts from 5 different colorectal tumours as well as with one 3 M KCl extract of normal colonic mucosa. Patients showing a pathological migration index (0.80 and 1.17), with 3 or more out of 5 tumour extracts, were considered as positives.With this test mode 93% (55/59) of patients with colorectal carcinomas were reactive, irrespective of the tumour stage, while only 7% (2/27) of patients with non-malignant colorectal diseases showed a positive reaction. Patients with malignant and non-malignant diseases of other organs were reactive in 2–3% of cases. No positive reactivity was observed with leukocytes from 37 healthy volunteers. Pulsing leukocytes with the normal colonic mucosal extract, a pathological migration index was found in about 20% of colorectal cancer patients, but not in healthy volunteers.Evaluating 10 single tumour extracts individually, reactivity of cancer patients' leukocytes ranged from 65–89% of tests, the difference being not statistically significant. Leukocytes from healthy volunteers showed a pathological migration index with the different extracts in 0–6% of tests.With the leukocyte migration test we could not differentiate between tumours of the colon, sigma or rectum. Patients bearing tumours in any part of the large bowel showed pathological leukocyte migration with extracts of colon-, sigma- and rectum tumours. When the cross-reactivity study was extended to tumours of the gastrointestinal tract, it was found that patients with colorectal tumours were reactive, in a high percentage of tests, with extracts of gastric tumours, but gastric as well as oesophageal and pancreatic cancer patients' leukocytes only reacted occasionally with colorectal tumour extracts.In the follow-up study, a positive reactivity was still found 10–14 days after surgery in 27/31 patients. After more than 2 months, the frequency of positive reactivity decreased to 10/70 cases. Patients with local recurrence or metastases exhibited positive reactivity in 6/7 cases.Abbreviations LMT leukocyte migration test - LM leukocyte migration - LMI leukocyte migration inhibition - LME leukocyte migration enhancement - MI migration index     

Preparation and long-term cultivation of porcine tracheal and lung organ cultures by alternate exposure to gaseous and liquid medium phases

Summary Conventional methods of organ culture have proved unsatisfactory for mammalian lung because of the rapid collapse of the tissue and the loss of its normal structure. In an effort to circumvent this problem and to provide a means for visualizing the cellular relationships throughout the culture period, respiratory organs consisting of trachea and lungs of fetal or hysterectomy-derived 1- to 4-week-old pigs were embedded in warm 3% Noble agar in phosphate buffer silicone solution and cooled to firmness. By use of a described cutting device, the respective organs were sliced into thin, 0.5- to 1.0-mm tracheal ring or lung explants. These organ sections then were cultured by exposure to alternate gaseous and liquid-medium phases by rotation (12 rev per hr) in sealed Leighton tubes fitted in a described rotator. In short-term culture experiments, explants were best maintained in a culture-support medium containing Eagle's minimal essential medium, 20% fetal bovine serum, 0.5% lactalbumin hydrolysate, and other supplements in a pH range of 6.5 to 8.2, and a NaCl concentration of 0.1m or less. By bright-field and scanning-electron microscopy, tracheal ring and lung explant cultures incubated for 2 months showed intact, uniform and active ciliated epithelial surfaces which compared favorably with those of fresh preparations. The lung cultures showed alveoli that remained expanded, and the cellular integrity of the tissues remained normal in appearance. This new method provides respiratory organs as continuous records with exceptional cellular clarity and readily available for histological processing. The organ cultures lend themselves well to pathogenesis studies in which subtle cellular changes or a sequence of changes induced in pulmonary tissues are difficult to observe in the host.     

Preparation and long-term cultivation of porcine tracheal and lung organ cultures by alternate exposure to gaseous and liquid medium phases.

Conventional methods of organ culture have proved unsatisfactory for mammalian lung because of the rapid collapse of the tissue and the loss of its normal structure. In an effort to circumvent this problem and to provide a means for visualizing the cellular relationships throughout the culture period, respiratory organs consisting of trachea and lungs of fetal or hysterectomy-derived 1- to 4-week-old pigs were embedded in warm 3% Noble agar in phosphate buffer silicone solution and cooled to firmness. By use of a described cutting device, the respective organs were sliced into thin, 0.5- to 1.0-mm tracheal ring or lung explants. These organ sections then were cultured by exposure to alternate gaseous and liquid-medium phases by rotation (12 rev per hr) in sealed Leighton tubes fitted in a described rotator. In short-,erm culture experiments, explants were best maintained in a culture-support medium containing Eagle's minimal essential medium, 20% fetal bovine serum, 0.5% lactalbumin hydrolysate, and other supplements in a pH range of 6.5 to 8.2, and a NaCl concentration of 0.1 M or less. By bright-field and scanning-electron microscopy, tracheal ring and lung explant cultures incubated for 2 months showed intact, uniform and active ciliated epithelial surfaces which compared favorably with those of fresh preparations. The lung cultures showed alveoli that remained expanded, and the cellular integrity of the tissues remained normal in appearance. This new method provides respiratory organs as continuous records with exceptional cellular clarity and readily available for histological processing. The organ cultures lend themselves well to pathogenesis studies in which subtle cellualr changes or a sequence of changes induced in pulmonary tissues are difficult to observe in the host.     

A mechanism of suppression of antitumor immunity (LAI reactivity) by surgery

Summary Antitumor immunity assayed by tube leukocyte adherence inhibition (LAI) is suppressed during and for up to 1–3 weeks after surgery. The results of this study suggest that when cortisol is elevated above physiologic levels by the stress of surgery this has a marked suppressive effect on the LAI-reactive cell. Cortisol added to the in vitro tube LAI assay had a two-phase effect. Cortisol at concentrations about two-fold above physiologic levels inhibited the sensitization of the peripheral blood leukocytes with cytophilic IgG antitumor antibody; however, if the cell was already armed, the cortisol did not negate its LAI reactivity. Higher concentrations of cortisol had a direct inhibitory effect on the LAI-reactive cells' ability to react with tumor antigen whether or not the cells were armed. In addition, the in vivo elevation of cortisol by the administration of cortisone acetate to LAI-positive patients inhibited the LAI reactivity of their leukocytes. Stress-induced elevation of cortisol by surgery may have an adverse effect on resistance to tumor growth, and the extent of the immunodepression may be one of the variables in the difference in survival of patients with cancers with similar degrees of invasion. Present address: 2911 Bayview Avenue, 206G, Willowdale, Ontario     

A systematic screen for genes expressed in definitive endoderm by Serial Analysis of Gene Expression (SAGE)

Background  

The embryonic definitive endoderm (DE) gives rise to organs of the gastrointestinal and respiratory tract including the liver, pancreas and epithelia of the lung and colon. Understanding how DE progenitor cells generate these tissues is critical to understanding the cause of visceral organ disorders and cancers, and will ultimately lead to novel therapies including tissue and organ regeneration. However, investigation into the molecular mechanisms of DE differentiation has been hindered by the lack of early DE-specific markers.