The level of expression of class-I MHC antigens in adenovirus-transformed human cell lines

Differential expression of LFA-3, Fas and MHC Class I on Ad5- and Ad12-transformed human cells and their susceptibility to lymphokine-activated killer (LAK) cells

Adenovirus (Ad) E1A is a potent oncogene and has been shown to deregulate the expression of a large number of cellular genes leading to cellular transformation. Here we have analysed the expression of several immunomodulatory molecules on the surface of a set of human cell lines transformed with either Ad12 or Ad5. Human cells transformed with Ad12 demonstrated reduced expression of cell surface LFA-3, Fas and MHC class I when compared to Ad5-transformed cells. Furthermore, Ad12-transformed human cell lines demonstrated greater susceptibility to lysis by lymphokine-activated killer (LAK) cells, compared to Ad5-transformed human cell lines. In contrast, previous studies with rodent cells showed that both Ad5- and Ad12-transformed rat cells were susceptible to LAK cells. Thus, transformation of human cells with Ad5 or Ad12 results in differences in the expression of immunomodulatory molecules on the cell surface and differential recognition of these virus-transformed cells by immune effector cells.

Frequency of abnormal expression of HLA-A,B,C and HLA-DR molecules, invariant chain, and LFA-3 (CD58) in colorectal carcinoma and its impact on tumor recurrence

HLA-A,B,C and HLA-DR molecules are involved in cognate LFA-3 (CD58) in antigen-independent T-cell/target-cell interaction. T-cell-mediated host-versus-tumor response might therefore depend on the presence of both types of molecules on the surface of the target cell. To investigate whether presence or absence of these molecules in colorectal carcinoma influences the recurrence rate, 149 patients who underwent curative surgery were surveyed for a maximum of 65 months (mean, 48 months). As determined by immunohistochemistry, aberrant reduction of HLA-A,B,C determinants was observed in 34.9 and a complete loss in 8.7% of the tumor specimens. An induction of HLA-DR molecules was found in 55.0 and of the HLA-DR-associated invariant chain (Ii) in 81.9%. An abnormal reduction of LFA-3 was detected in 43.6%, while a complete loss of this structure was observed in 6.7%. Reduction/loss of HLA-A,B,C was correlated with reduction/loss of LFA-3 (p = 0.03). In contrast to the prognostic role of tumor stage and grade, the presence vs. absence of all these structures was not correlated with the recurrence rate. We conclude that, although encoded on different chromosomes, an abnormal reduction/loss of HLA-A,B,C and LFA-3 might be the consequence of one transacting down-regulating signal. However, the resulting deviant immunophenotypes do not profoundly influence survival and growth potential of residual tumor cells.

Expression of HLA-A,B,C, beta 2-microglobulin (beta 2m), HLA-DR, -DP, -DQ and of HLA-D-associated invariant chain (Ii) in soft-tissue tumors

Non-neoplastic mesenchymal cells, along with 33 benign and 87 malignant soft-tissue tumors (STT) were examined for expression of HLA-A,B,C, beta 2-microglobulin (beta 2m), HLA-DR, -DP, and -DQ molecules and the HLA-D associated invariant chain (Ii). Serial frozen sections were immunostained using monoclonal antibodies (MAbs) to monomorphic framework determinants of HLA sublocus products, beta 2m and Ii, and to CD53, a recently defined broadly distributed pan-leucocyte molecule. Compared with the normal state, an induction/neo-expression of HLA-A,B,C/beta 2m was found in a considerable number of tumors of muscle, peripheral nerve, cartilage-forming, adipose, and vascular tissues. Conversely, some tumors of fibrous origin and of autonomic ganglia showed an abnormal abrogation/loss of HLA-A,B,C/beta 2m with respect to their cells of origin. Small, round tumor cells present in various types of STT exhibited a heterogenous pattern of expression of these molecules with a preponderance of HLA-A, B,C/beta 2m-negativity. HLA-D/Ii determinants were rarely detectable in STT. Besides their expression in some fibrohistiocytic tumors, they were only occasionally found in tumors of smooth-muscle, peripheral-nerve and vascular origin as well as in one clear-cell sarcoma. In all tumors but one, there was no microtopographic association between HLA-D/Ii-positive tumor cells and inflammatory cells. CD53 allowed discrimination between dendritic interstitial cells (DIC) and neoplastic cells and additionally revealed that, in contrast to other solid tumors, STT are generally characterized by an extreme scarcity of lymphohistiocytic infiltrates. Our data indicate that, aside from very rare exceptions, aberrant induction or abrogation of MHC molecules in STT occurs in the absence of lymphohistiocytic stromal infiltrates, suggesting that these alterations might not be a consequence of local cytokine effects.

Immunohistological characteristics of the infiltrating lymphoid cells and expression of HLA class I and II antigens in nasopharyngeal carcinoma

The immunohistological characteristics of infiltrating lymphoid cells and the expression of human leucocyte antigens class I and II (HLA-ABC and HLA-DR, respectively) were studied in 50 pre-treatment nasopharyngeal carcinomas. The majority of lymphoid cells were activated lymphocytes expressing thymocyte OKT10 marker. CD4+ cells (T-helper/inducer) out-numbered CD8+ cells (T-suppressor/cytotoxic) by at least two- to four-fold. CD22+ cells (pan-B lymphocytes) were scanty in the peri-tumoral areas and were absent in 29 out of 50 biopsies. A moderate number of cells expressing CD15 (monocytes/macrophages) were also detected. CD16+ cells (natural killer cells) were found to be sparse or absent. Expression of HLA class I and II antigens on the tumor cells in 35 biopsies was variable. HLA-ABC staining was intense in 6, reduced in 13 and partially lost in 16, whereas staining of HLA DR was intense in 7, reduced in 11 and partially lost in 17. Full expression of both antigens was demonstrable in only 2 biopsy samples. The expression of HLA antigens in the tumour had no relationship to the type or degree of lymphocytic infiltration or staging of the tumour.

Inhibitory effect of interferon-gamma on adenovirus replication and late transcription

We have previously shown that human interferon-gamma inhibited adenovirus multiplication in vitro in a dose-dependent fashion. This action was previous to capsid proteins synthesis and did not involve virus adsorption nor penetration. In this report we have analysed viral mRNA levels at early (7 hr post infection (p.i.)) or late (20 hr p.i.) times, as well as DNA replication in Wish cells pretreated with interferon-gamma and infected with adenovirus 5. Controls included untreated cells as well as cells treated with interferon-alpha, to which adenovirus are reported to be resistant. Transcription of adenovirus regions E1, E4, L1 and L2 has been analysed by Northern blot. Adenovirus DNA replication was determined by DNA-DNA hybridization with total adenovirus 2 DNA. We have also searched for adenovirus E1A proteins by immunoblot with a specific monoclonal antibody. Although pretreatment of cells with either interferon-alpha or interferon-gamma resulted in reduced amounts of E1 and E4 mRNA in the early phase of infection (7 hr p.i.), the near complete inhibition of viral DNA and late transcription was only achieved by interferon-gamma. Immunoblot has shown the absence of the 48-kD E1A protein in cells pretreated with interferon-gamma. The lack of this regulatory adenovirus protein may be involved in the inhibitory mechanism of interferon-gamma on adenovirus.

Acquisition of tumorigenic potential in the human myoepithelial HBL100 cell line is associated with decreased expression of HLA class I, class II and integrin beta 3 and increased expression of c-myc

The human breast cell line HBL100 acquires the capacity to invade normal tissues and to replace them by proliferation in vitro only at high passage levels (HPL). These cells therefore are a useful model for studying tumor progression in vitro. We have analyzed the expression of cell-surface markers supposed to be involved in the control of the neoplastic process. Quantitative flow cytometry has revealed that: (1) spontaneous expression of HLA class-I antigens strongly decreases in HPL HBL100 cells vs. LPL cells, which parallels amplification and over-expression of c-myc oncogene; (2) HLA DR antigens can be induced by IFN-gamma in LPL but not in HPL HBL100 cells; (3) HBL100 cells secrete a soluble protein factor which specifically inhibits HLA DR induction by IFN-gamma even in heterologous cell systems; (4) 50% of LPL HBL100 cells express integrin beta 3, whereas HPL HBL100 cells lose this antigen; (5) this cell line is myoepithelial in origin, since 100% of HBL100 cells exhibit the CD10 antigen. Our data stress a role of HLA antigens, of some integrins and of c-myc in the acquisition of malignant potential by myoepithelial mammary cells of the HBL100 line.