Immunobiologic Aspects of Head and Neck Cancer: Clinical and Laboratory Correlates

Human Head and Neck Squamous Cell Carcinoma-Associated Semaphorin 4D Induces Expansion of Myeloid-Derived Suppressor Cells

One of the mechanisms by which malignancies can induce immune suppression is through the production of cytokines that affect the maturation and differentiation of inflammatory cells in the tumor microenvironment. Semaphorin 4D (Sema4D) is a proangiogenic cytokine produced by several malignancies, which has been described in the regulation of the immune system. In the present study, we examined the role of human head and neck squamous cell carcinoma (HNSCC)-secreted Sema4D on myeloid cell differentiation. CD33(+) cells cultured in HNSCC cell line-derived conditioned medium differentiated into myeloid derived suppressor cells (MDSC) (CD33(+)CD11b(+)HLA-DR(-/low)). The addition of anti-Sema4D Ab to HNSCC conditioned medium significantly reduced the expansion of the MDSC population. Similarly, knockdown of Sema4D in an HNSCC cell line resulted in a loss of MDSC function as shown by a decrease in the production of the immune-suppressive cytokines arginase-1, TGF-β, and IL-10 by MDSC, concomitant with recovery of T cell proliferation and IFN-γ production following stimulation of CD3/CD28. Importantly, CD33(+) myeloid and T cells cultured in conditioned medium of HNSCC cells in which Sema4D was knocked down promoted antitumor inflammatory profile, through recovery of the effector T cells (CD4(+)T-bet(+) and CD8(+)T-bet(+)), as well as a decrease in regulatory T cells (CD4(+)CD25(+)FOXP3(+)). We also showed that Sema4D was comparable to GM-CSF in its induction of MDSC. Collectively, this study describes a novel immunosuppressive role for Sema4D in HNSCC through induction of MDSC, and it highlights Sema4D as a therapeutic target for future studies to enhance the antitumorigenic inflammatory response in HNSCC and other epithelial malignancies.

Assessment of p38α in peripheral blood mononuclear cells (PBMC): a potential blood protein marker of head and neck squamous cell carcinoma

PURPOSE

Solid tumors involve an inflammatory microenvironment portrayed by immune cells playing role in cancer progression via inflammatory p38α mitogen-activated protein kinase (MAPK) molecule that produces pro-inflammatory cytokines-TNFα, IL1β and IL6. This study quantified and compared the expression of p38α in peripheral blood mononuclear cells (PBMCs) of HNSCC patients with the healthy subjects.

METHODS

The PBMC were isolated from the 35 control and 83 HNSCC patients. The expression of p38α in PBMCs was assessed using surface plasmon resonance (SPR), ELISA and western blot analysis.

RESULTS

p38α levels were found to be over-expressed in HNSCC patients 0.98 ng/μl (95 % CI 0.95-1.02) as compared to controls 0.46 ng/μl (95 % CI 0.42-0.50) (p < 0.0001).

CONCLUSION

p38α is over-expressed in PBMCs of HNSCC patients and may play a role in the progression of cancer. This research may translate a protein marker for HNSCC to clinical oncologist for therapeutic intervention and use as a predictive marker.

Tumors induce the formation of suppressor endothelial cells in vivo

Patients with solid tumors have defects in immune effector cells, which have been associated with a poorer prognosis. Previous studies by our laboratory have shown that exposure to Lewis lung carcinoma (LLC)- secreted products induces the formation of suppressor endothelial cells in vitro. The current studies examined if tumors could induce the formation of suppressor endothelial cells in vivo. Endothelial cells were immunomagnetically isolated from the lungs of tumor-bearing mice or normal controls and examined for their ability to modulate NK cell, T-cell and macrophage functions. Compared to normal controls, supernatants from endothelial cells isolated from tumor-bearing lungs had elevated secretion of PGE2, IL-6, IL-10 and VEGF. Conditioned media from endothelial cells isolated from normal lungs increased CD8+ T-cell IFN-γ and CD4+ T-cell IL-2 production in response to anti-CD3 stimulation, while media conditioned by endothelial cells from tumor-bearing lungs had a diminished stimulatory capacity. Examination of NK cell functions showed that supernatants from endothelial cells isolated from normal lungs were potent activators of NK cells, as indicated by their secretion of TNF- and IFN-γ. Endothelial cells isolated from tumor-bearing lungs had a significantly diminished capacity to activate NK cells. Finally, supernatants from endothelial cells of tumor-bearing lungs diminished macrophage phagocytosis compared to either treatment with supernatants of normal endothelial cells or treatment with media alone. The results of these studies demonstrate that tumors induce the formation of suppressor endothelial cells in vivo and provide support for the role of endothelial cells in tumor-induced immune suppression.

Mononuclear phagocytes in head and neck squamous cell carcinoma

The head and neck squamous cell carcinoma microenvironments contain many immune cells and their secretory products. Many of these cells belong to the mononuclear phagocyte system. The aim of this review is to study the interactions between mononuclear phagocytes and head and neck squamous cell carcinoma tissue. The role of inflammation in tumours and the cytokine interleukin-6 will be highlighted. Future therapy strategies in the treatment of head and neck cancer might be directed towards mononuclear phagocytes and their cytokine production.

Impaired monocyte function in cancer patients: restoration with a cyclooxygenase-2 inhibitor

Epidemiological data and animal models have provided evidence that nonsteroidal antiinflammatory drugs (NSAIDs) have an anticancer effect. However, the molecular mechanisms underlying these antineoplastic effects are not well understood. We described previously that expression levels of the chemokine receptor, CCR5, and the beta2-integrin, Mac-1, were down-regulated on primary monocytes after incubation in supernatants from human carcinoma cell lines, and that this down-regulation resulted in impaired monocyte function with respect to migration and adhesion. We now demonstrate that these impairments are also present in vivo. Monocytes from cancer patients displayed significantly reduced CCR5 levels and migration capacities in comparison to cells from healthy donors. Because migration is necessary for the antitumor activity of monocytes/macrophages, these deficits may contribute to the suppressed immune system seen in cancer patients. In a clinical study, we analyzed the effect of a selective COX-2 inhibitor, Rofecoxib, on the migration of monocytes derived from cancer patients. The results revealed significant improvement in migration equal to those levels seen in healthy donors. We conclude that in patients with cancer, the intake of Rofecoxib for 3 wk leads to significant restoration of monocyte function. These data may, at least in part, help explain the anticancer effects of NSAIDs.

Lymphoid cell infiltration into Epstein-Barr virus-positive nasopharyngeal carcinomas

OBJECTIVES

A pilot study was designed to analyze lymphoid cell infiltration in Epstein-Barr virus-positive (EBV+) nasopharyngeal carcinomas (NPCs) and to determine whether this pattern of infiltration is consistent with non-EBV+ head and neck carcinomas or with solid EBV+ tumors in other locations.

STUDY DESIGN

We performed a retrospective analysis of archived NPCs and oral cavity carcinomas.

METHODS

Immunohistochemical staining of the archive material for various markers (CD3, CD8, UCHL-1, S-100, and intercellular adhesion molecule) was performed. Polymerase chain reaction techniques to establish the presence of the EBV genome were used. Cells in different locations were counted under a light microscope by 2 of the authors.

RESULTS

The infiltration pattern of NPCs was different from that of oral cavity carcinomas. Stromal infiltration was significantly denser in oral cavity carcinomas. Tumor nest infiltration was more pronounced in NPCs. The pattern of infiltration was comparable with what has been described for other solid EBV+ tumors.

CONCLUSIONS

The immune response to NPCs is likely to be strongly influenced by the presence of the EBV genome. The pattern of infiltration is similar to that of other non-head and neck EBV+ solid tumors and different from that of EBV- head and neck carcinomas.

CD34+ immune suppressive cells in the peripheral blood of patients with head and neck cancer

Patients with head and neck squamous cell carcinoma (HNSCC) have profound defects in their immune defenses. Using immunofluorescent staining and flow cytometric analysis, we found that most patients with HNSCC have increased levels of CD34+ cells within their peripheral blood. These circulating CD34+ cells contribute to the depressed functional competence of the peripheral blood T-lymphocytes. This was demonstrated by the increased level of proliferative responsiveness to interleukin-2 by the patients' peripheral blood T-cells after depletion of CD34+ cells. These results show the importance of CD34+ cells in contributing to the depression of T-lymphocyte function in patients with HNSCC and suggest that strategies designed to reduce the levels of circulating CD34+ cells may enhance the immune reactivity of the patients' circulating T-lymphocytes against the HNSCC.

Peripheral blood T-lymphocyte and monocyte function and survival in patients with head and neck carcinoma

OBJECTIVES/HYPOTHESIS

To determine if the T-lymphocyte and monocyte functions of peripheral blood mononuclear cells (PBMCs) from patients with head and neck squamous cell carcinomas (HNSCC) are predictive factors for outcome.

STUDY DESIGN

A prospective study describing the outcome, as to total survival and death by disease after at least 40 months observation, of 81 previously untreated male HNSCC patients in relation to PBMC T-lymphocyte and monocyte function.

METHODS

T-lymphocyte mitogenesis and the cytokine level in culture supernatants of PBMC as well as monocytes were analyzed. These parameters were related to survival by Cox regression and Kaplan-Meier survival analysis.

RESULTS

When patients with high versus low T-lymphocyte mitogen-stimulated proliferations were compared, a decreased proliferation was seen to be related to worse outcome. The predictive value of T-lymphocyte proliferation was shown to be an independent prognostic factor when adjusted for stage and stratified for anatomic location in survival analysis. The predictive value was also retained when the serum values of the major serum proteins and hormones and scores based on the smoking and alcohol history were added to the survival analysis with lymphocyte proliferation. Supernatant levels of gamma-interferon, interleukin (IL)-2, or IL-4 in PBMC cultures were not related to outcome. Monocyte function measured by endotoxin-stimulated IL-1beta, IL-6, IL-12, and tumor necrosis factor-alpha secretion did not relate to outcome of the patients.

CONCLUSION

The PBMC T-lymphocyte-stimulated proliferation is an independent prognostic factor for male HNSCC patients.

Myeloid progenitor cells mediate immune suppression in patients with head and neck cancers

Patients with squamous cell carcinomas of the head and neck (HNSCC) have profound defects in their immune defenses. We have shown that among the mechanisms that contribute to this immune dysfunction are immune inhibitory CD34+ progenitor cells, whose levels become elevated in the peripheral blood and within the tumor tissue. One goal of our studies is to overcome the immune inhibitory activities of tumor-induced CD34+ progenitor cells by stimulating their differentiation into cells, such as dendritic or monocytic cells, that can stimulate immune reactivity to autologous cancer. Results of in vitro analyses with CD34+ suppressor cells of HNSCC patients and of in vivo studies in animal tumor models have shown the capacity of tumor-induced CD34+ cells to differentiate into cells that phenotypically resemble monocytic or dendritic cells. Whether these cells can differentiate into dendritic cells in HNSCC patients is currently being tested. Less clear is whether the pathway by which the tumor-induced CD34+ cells differentiate will result in cells having the full capacity to function as potent stimulators of immune reactivity to autologous tumor.

Peripheral blood mononuclear cell (PBMC) responsiveness in patients with head and neck cancer in relation to tumour stage and prognosis

We have previously shown an increased T lymphocyte and monocyte responsiveness in peripheral blood mononuclear cells (PBMC) from patients with head and neck squamous cell carcinoma (HNSCC) compared with PBMC from control patients. This study reports T lymphocyte function of PBMC of 81 patients with HNSCC dependent on disease stage and prognosis. Males with HNSCC under 80 years of age without cachexia, with no auto-immune disease or previous cancer and on no immuno-active medication were included at the time of diagnosis of disease. The follow-up was for at least 18 months. When cells from patients with early vs late stage disease according to the T, N or T + N stage of HNSCC were compared, decreased in vitro mitogen-stimulated and spontaneous T cell proliferation was seen with increasing tumour stage. When patients were studied according to disease-specific survival, a decreased T lymphocyte mitogen-stimulated proliferation was observed to be associated with a poorer prognosis. No changes in prognosis were noticed related to decreased gamma-IFN, IL-2 or IL-4 level of the supernatants of the T lymphocyte-stimulated PBMC in vitro cultures. With stratification for disease stage, we determined that PBMC in vitro T lymphocyte-stimulated proliferation predicted outcome for the HNSCC patients. The results were similar for both laryngeal and oral cavity/pharyngeal cancers. The present investigation provides evidence to support the idea that the relationship between HNSCC and the immune system of the host may provide clinically useful information about prognosis.

Mechanisms of immune suppression in patients with head and neck cancer: influence on the immune infiltrate of the cancer

Freshly excised human head and neck cancers (219 primary cancers; 64 metastatic lymph node cancers) were analyzed for the immune inhibitory mediators released from the cancer tissues and the immune infiltrate within the tumor. Significant levels of the immune inhibitory mediators transforming growth factor-beta (TGF-beta), prostaglandin E2 (PGE2) and interleukin-10 (IL-10) were released from these cancers. Also released was granulocyte-macrophage colony-stimulating factor (GM-CSF), whose secretion was associated with an intratumoral presence of CD34+ cells. We have previously shown that CD34+ cells within human head and neck cancers are immune inhibitory granulocyte-macrophage progenitor cells. The presence of TGF-beta, PGE2 and IL-10 was associated with a reduced content of CD8+ T-cells within the cancers. The CD4+ cell content appeared to be less affected by these immune inhibitory mediators. Instead, parameters indicative of CD4+ cell function (p55 IL-2 receptor expression, release of IL-2 and IFN-gamma) were diminished in cancers that released higher levels of TGF-beta, IL-10 and GM-CSF and had a higher CD34+ cell content. Furthermore, metastatic cancers released higher levels of the soluble immune inhibitory mediators and lower levels of IFN-gamma and IL-2 than did primary cancers, although CD34+ cells were similarly present in both primary and metastatic cancers. Our results show that human head and neck cancers have a multiplicity of non-mutually exclusive mechanisms of immune suppression that are most prominently associated with reduced CD8+ cell influx and reduced influx and altered function of intratumoral CD4+ cells.

Thymostimulin enhancement of T-cell infiltration into head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) produces immunosuppressive low-molecular-mass factors (LMMFs) responsible for defects in the cell-mediated immune system. These defects include impaired monocyte chemotaxis and an impaired capability of dendritic cells (DC) to form cellular clusters. It has been shown previously that the immunomodulating drug thymostimulin (TP1) restores these defects in vitro.

METHODS

An immunohistochemical study was performed on tumors of 18 patients with HNSCC who had preoperatively been treated with TP1 in one of three dosages (0.5 mg/kg, 1.0 mg/kg, 2.0 mg/kg body weight). Additionally, tumors of 4 patients who had been treated with a placebo and 12 patients who had not received any preoperative treatment were studied. A relative surface area of infiltration, meaning the percentage of stromal or epithelial tissue covered by infiltrating cells in histological sections, was calculated using an image analysis system (VIDAS RT) for CD3+ T-cells, CD14+/CD68+ monocytes/macrophages and L25+/CD1a+ dendritic cells for each tumor.

RESULTS

A highly significant, denser T-cell infiltration into the stromal tissue area of tumors of patients who had been treated with TP1 when compared with tumors of non-TP1-treated patients was observed for all three dosages. None of the other tumor-infiltrating cell types was affected by TP1. In addition, a correlation was found between the tumor T-cell infiltration and capability of DCs in the peripheral blood to form clusters with T-cells. No correlation existed between CD3+ T-cell numbers in peripheral blood and T-cell infiltration into the tumor; nor were monocyte chemotactic functions in peripheral blood correlated with tumor infiltration by monocytes or monocyte-derived macrophages and DCs.

CONCLUSIONS

Preoperative treatment of HNSCC patients with TP1 appears to strongly enhance tumor--T-cell infiltration. The number of tumor-infiltrating DCs was not affected by TP1, but a positive correlation between tumor--T-cell infiltration and DC clustering capability suggests that the functional status of DCs is important in improved cell-mediated immunity.

Circulating immune complexes in intracranial neoplasms

The levels of circulating immune complexes (CIC) were assayed in the sera of 109 patients with intracranial space occupying lesions. The CIC levels were significantly increased in all the brain tumours. After treatment, the CIC levels were still significantly increased when compared to the controls but showed no change when compared to their respective pre-operative values. Further, no change was observed in the CIC levels between the malignant and benign tumour case. Moreover, in brain tumours, 90% of the CIC precipitate consisted of IgG. However, the CIC levels fail to prognosticate the process of the disease in these patients.

Relation between age and head and neck cancer recurrence after surgery: a multivariate analysis

Recent reports have described an increase in squamous cell carcinoma of the upper aerodigestive tract in young adults. As the preponderance of epidemiologic data exists for the population between 50 and 70 years of age, controversy has developed regarding the clinical course of head and neck cancer in youth. Some authors advocate more aggressive management, calling attention to the lack of "classic" predisposing factors and suggesting genetic disorders or immunodeficiency. Basic science researchers have reported greater DNA fragility, sensitivity to carcinogens, and altered immune responses in young patients with carcinoma. To further elucidate the clinical aspects of this controversy, we performed a retrospective review using multivariate analysis to determine factors that affect recurrence. After screening 820 charts, 155 patients were found who met strict entrance criteria to the study. The patients were separated into five age groups, and 16 clinical variables were collected on each patient. Cox proportional hazards modeling revealed no significantly higher likelihood of recurrence in the 15- to 39-year-old age group. The model did find that metastatic adenopathy was predictive of recurrence (p = 0.034). The overall model further suggested a trend toward higher relative risk of recurrence in the middle-aged groups (p = 0.0541). In our review of the English biomedical literature, this is the first study to directly compare the outcome of young head and neck cancer patients with that of old patients using multivariate analysis. Future research is indicated in developing precise outcome predictions according to TNM staging, aneuploidy status, and DNA fragility in young patients. Efforts at limiting carcinogen exposure should continue.

Prognostic significance of clinically false positive cervical lymph nodes in patients with laryngeal carcinoma

BACKGROUND

A significant proportion of clinically positive palpable cervical lymph nodes in patients with head and neck cancer are histologically benign. The biologic and prognostic significance of this reactive lymph node enlargement has not been fully clarified.

METHODS

In this study, the incidence of clinically positive microscopically negative cervical lymph nodes in a series of 902 patients who had neck procedures as a part of their primary treatment for N0-2 laryngeal cancer was analyzed and survival rates of 342 patients with true negative lymph nodes (N0- necks) were compared with those of 106 patients with clinically false positive lymph nodes (N1-2b- necks). In 86 patients with false positive lymph nodes, a histopathologic analysis was performed to determine the histomorphologic pattern of the enlarged lymph nodes and to evaluate which parameters, if any, correlated with 5-year patient survival.

RESULTS

Overall actuarial survival did not differ significantly in the two groups. However, the actuarial survival curves in the false positive group were clearly better compared with those of the true negative group with more advanced laryngeal cancers, particularly T4 lesions (P < 0.05). Interestingly, the analysis of pattern of recurrence showed a higher incidence of distant metastases in false positive patients with advanced stage laryngeal cancer than in true negative subjects. In addition, the histologic examination of 375 enlarged hyperplastic cervical lymph nodes from 86 neck specimens showed the prevalence of sinus histiocytosis in the false positive group and its favorable prognostic significance. No statistically significant differences with regard to the number and size of enlarged lymph nodes were found. On the contrary, lymph node location seems to have a prognostic impact on survival and the reactive benign enlargement of a digastric lymph node is a possible poor prognostic factor.

CONCLUSIONS

Survival of patients with clinically false positive, histologically benign hyperplastic cervical lymph nodes who have more advanced laryngeal carcinoma is higher than clinically negative patients, suggesting that the presence of palpable benign nodes may be a sign of the host's immune activation, with favorable prognostic significance.

Interferons and other cytokines in head and neck cancer

The use of cytokines in head and neck cancer is increasingly under investigation. Clinical trials have tested the interferons, interleukin-2 and other cytokines as single agents and in various combinations. The addition of interferon to the cisplatin and 5-fluorouracil (5-FU) regimens (with and without leucovorin) has been explored. A randomized international trial comparing cisplatin and 5-FU with cisplatin, 5-FU and interferon-alpha 2b is in progress.

In vivo infiltration of mononuclear cells in squamous cell carcinoma of the head and neck correlates with the ability to expand tumour-infiltrating T cells in vitro and with the expression of MHC class I antigens on tumour cells

A series of 18 head and neck squamous cell carcinoma biopsies, 6 primary and 12 recurrent, were investigated for tumour-infiltrating mononuclear cells with monoclonal or polyclonal antibodies. Our results suggest that the number of T cells at the tumour edge in vivo correlates well with their ability to expand in vitro in the presence of high-dose interleukin-2 (2000 U/ml). High MHC class I antigen expression on tumour cells was found to be positively correlated with p53 overexpression, suggesting that p53-derived peptides, wild-type or mutated ones, presented by MHC class I antigens, are potential targets for MHC-restricted cytotoxic T cells in head and neck squamous cell carcinomas. However, lack of correlation between peritumoural T cell infiltration in vivo and T cell expansion in vitro, on the one hand, and p53 overexpression on tumour cells, on the other hand, suggests absence of p53-peptide-specific T cells in the patients. Eight out of ten expanded tumour-infiltrating lymphocyte (TIL) cultures showed T-cell-mediated cytotoxicity. "Promiscuous" cytotoxic T cell activity against the natural-killer-cell-sensitive K562 target cell line was observed in three out of ten TIL expansion cultures.

Functional and phenotypic analysis of T-lymphocytes in laryngeal carcinoma

We studied the functional response and phenotypic characterization of peripheral blood T cells and their correlation with the clinical stage of disease in 29 males with previously untreated carcinoma of the larynx and 24 healthy male controls. Peripheral blood T cells, phenotypically CD2+ CD3+, were significantly decreased in the patients relative to the controls. Patients with advanced locoregional extension (T4 and N1, 2, 3) also showed a diminution of the CD4+ subpopulation of T cells. DNA synthesis by purified T cells showed similar blastogenic responses in patients and controls; the interleukin-2 production of phytohemagglutinin stimulated lymphocytes was also normal. We conclude that in patients with laryngeal carcinoma there is a phenotypic alteration of the T cells that is variable according to tumor stage, without functional alterations in blastogenic capacity or IL-2 production.

Contribution of serum inhibitory factors and immune cellular defects to the depressed cell-mediated immunity in patients with head and neck cancer

The immune system of patients with head and neck cancer is frequently depressed. Serum inhibitory factors and immune cell dysfunction are known contributors to this depression, but their relative roles are unclear. We have examined these factors to determine whether a common pathway is involved. Is the defect an unresponding "switched-off cell" or is it a remedial defect responsive to the removal of serum inhibitory factors and/or to lymphokine restoration? Immune tests were performed in 66 patients with high-stage head and neck cancer. Serum inhibitory factors were measured by incubation of heat-inactivated serum (10%) with phytohemagglutinin (PHA)-stimulated lymphocytes or natural killer (NK) cells using the K562 assay. Lymphokine-activated killer (LAK) cell cytotoxicity was measured (in the presence/absence of serum) using chromium 51-labeled Raji tumor cells cultured 5 days with interleukin-2 (IL-2) (100 or 1,000 U/mL) and/or interferon-alpha (INF-alpha) (100 U/mL). IL-2 receptors, CD25 or p55 (low affinity) and p75 (high affinity), were measured by flow cytometry through fluorescence-activated cell sorter analysis. Serum inhibitory factors were detected in more than 50% of the patients. Head and neck cancer sera significantly inhibiting the normal lymphocyte response to PHA (11 of 22 patients), as well as significantly inhibiting the NK response of normal lymphocytes and the functional expression of the IL-2 receptor. LAK cell function at low-dose IL-2 was depressed in 45% of the patients (9 of 20) and was restored by increased IL-2 (1,000 U/mL) or a combination of IL-2 and INF-alpha. Twenty-five percent of the patients were unresponsive to maximum lymphokine stimulation. Half of the patients had depressed expression of the low-affinity IL-2 receptor (CD25). The cause of immune depression in patients with head and neck cancer is multifactorial and is related to serum inhibitory factors, as well as to inherent cellular defects. Based on these data, we would suggest a therapeutic approach in selected patients that includes the removal of serum inhibitory factors by plasmapheresis and restoration of cellular defects by combined IL-2 with or without INF-alpha.

Serum adenosine deaminase activity in brain tumours

Adenosine deaminase (ADA) activity in serum was estimated in 86 patients with intracranial tumours and 40 healthy volunteers. Although high ADA concentrations in biological fluids and tumour tissues were observed in several neoplastic conditions, there was no significant difference in the ADA in sera of brain tumour patients when compared to the control values. Therefore, cell-mediated immunity probably does not play a significant role in brain tumours.

Isolation and purification of a squamous cell carcinoma of the head and neck-associated antigen identified by autologous antibody

We have previously shown that detection of autologous antibody activity to squamous cell carcinoma of the head and neck may be augmented by dissociation of immune complexes. Western blot analysis with autologous antibody has identified a 60 kDa squamous cell carcinoma of the head and neck-associated antigen in spent media and immune complex-dissociated serum ultrafiltrate not recognized by normal human sera. Antigen-containing fractions of spent media were eluted from anion exchange columns immediately after serum albumin indicating that the antigen has an acidic pI < 4. Preparative purification of the squamous cell carcinoma antigen was accomplished by anion exchange of concentrated spent media (protein concentration 300 mg/ml) followed by lectin affinity chromatography with a Triticum vulgaris column. A single 60 kDa band was detected by silver stain and Western blot in antigen-containing fractions eluted following lectin affinity chromatography and SDS-PAGE. Final concentration of the antigen was determined to be 1 microgram/ml of protein with relative activity increased 1600 x over unfractionated spent media. We conclude that a squamous cell carcinoma of the head and neck-associated antigen, detected by autologous antibody, is an acidic 60 kDa glycoprotein.