MN Antigen Research Articles

Association of high levels of α-defensins and S100A proteins with Candida mannan detection in bronchoalveolar lavage fluid of preterm neonates

Candida mannan (Mn) detection in bronchoalveolar lavage fluid (BALF) was shown to be useful for earlier identification and preemptive therapy targeting in preterm infants at high risk of invasive Candida infection. We investigated whether early detection of Candida Mn in BALF is associated with the presence of some neutrophilic products, as markers of prenatal infection/inflammation. BALF specimens were collected during the first 48 h of life from mechanically ventilated preterm newborns. Samples were analyzed by high-performance liquid chromatography-electrospray ionization-mass spectrometry. The relative amounts of α-defensins 1-4 and S100A proteins were measured by extracted ion current peak area. Absolute and differential white cell counts in BALF were obtained. Mn antigen concentrations were determined by the Platelia Candida antigen kit. Twenty-five studied neonates were divided into two groups: Mn-positive group and Mn-negative group. Levels of α-defensins 1-4 and S100A12 were significantly higher in the Mn-positive group than in the Mn-negative group. Moreover, positive significant correlations between the absolute number of neutrophils and the levels of α-defensins 1-4 and S100A8 were observed. The detection of Mn antigen in BALF of preterm infants is consistent with evidence of an innate immune response in their lungs as demonstrated by higher levels of α-defensins and S100A proteins.

Early Mannan Detection in Bronchoalveolar Lavage Fluid With Preemptive Treatment Reduces the Incidence of Invasive Candida Infections in Preterm Infants

Candida colonization is an important predictor for development of invasive fungal infection (IFI). We investigated whether early detection of Candida mannan (Mn) in bronchoalveolar lavage fluid (BALF) reduces IFI among preterm infants. We conducted an observational study of infants with gestational age of < or =28 weeks, where a group undergoing Candida surveillance cultures (pre-Mn detection group) was compared with a group defined after the initiation of routine use of Candida Mn detection in BALF (Mn detection group). Antifungal treatment was started based on positive microbiologic (surveillance culture or Mn-antigen assay) results. No significant differences were detected when the groups were compared for several predictors of IFI. IFI was observed for 12 (23%) of 51 infants in the pre-Mn detection group, and for 0 (0%) of 29 infants in the Mn detection group (P = 0.003). Surveillance cultures in the pre-Mn detection group became positive at 15.0 +/- 7.2 days after birth, whereas the mean age at time of positive Mn antigen results in the Mn detection group was 4.3 +/- 3.1 days (P < 0.0001). Among 16 infants positive for surveillance cultures, 12 (75%) developed IFI (P < 0.0001). This study suggests that Candida Mn detection in BALF may be useful for earlier identification and preemptive therapy targeting preterm infants at high risk of IFI.

Results of a phase I/II study with monoclonal antibody CG250 in combination with IFN α-2A in metastatic renal cell carcinoma patients

4606 Background: cG250 (WX-G250, Renecarex) is a chimeric monoclonal antibody of IgG1 subtype that binds to the cell surface antigen of carboxyanhydrase IX (MN antigen) that is found on 95% of clear cell RCC cells but not on normal kidney tissue. A multi-center, open-label, prospective, single-arm phase I/II trial study has been performed, evaluating the safety and efficacy of repeated doses of WX-G250 in combination with IFN α-2a in a total of 32 patients with metastatic RCC. Methods: Patients with stage IV renal cell carcinoma, nephrectomy for the primary tumor, in progression at study entry and with measurable bidimensionally disease between ≥1 cm and ≤5 cm in diameter were included in the study. WX-G250 was applied once weekly for 3 months at 20 mg by iv infusion (total dose). In addition, patients were treated with IFN α-2a, 3 MIU, 3 times per week subcutaneously. In week 16, in the event of stable disease or tumor response, continuation of treatment with the WX-G250 for 6 more weeks was offered. Results: Of 32 enrolled patients, 31 patients could be analyzed. The safety population patients (n = 31) experienced a total of 183 adverse events (AEs). The AEs which were definitely related to study medication (39/183, 25.8%) were of toxicity grade 1 and 2. They mainly comprised ‘constitutional symptoms’ (22 AEs, 25.8%) and ‘pain’ (13 AEs, 12.9 %), described as typical side effects of the treatment with cytokines. No immunological response (HACA) could be detected during the course of WX-G250 treatment. Tumor assessment was performed by the investigators by computertomography (CT)-evaluation. Preliminary primary efficacy results were determined by tumor assessment in week 16 with 83.3% of the patients (N=26). 11.5% (N=3) of these patients showed PR, 46.2% (N=12) SD and 42.3% (N=11) PD. All results are subject to further evaluation by an independent radiologist. Data collection on TTP and OS are still ongoing. Conclusions: Treatment with WX-G250 is generally safe and well tolerated. Objective tumor responses and disease stabilization can be considered as clinically meaningful and are of clinical benefit for this metastatic patient population. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Wilex AG Wilex AG

Candidate HIV/AIDS vaccines

Candidate HIV/AIDS vaccines

Targeting Hyperthermia for Renal Cell Carcinoma Using Human MN Antigenspecific Magnetoliposomes

Magnetoliposomes (MLs) conjugated with an antibody fragment to give specificity to a tumor were applied to hyperthermia for cancer. The Fab' fragment of the G250 antibody, which binds to MN antigen on many types of human renal cell carcinoma, was cross–linked to Af–(6–maleimidocaproyl–oxy)–dipalmitoyl phosphatidylethanolamine (EMC–DPPE) in liposomal membrane. The targetabil–ity of the G250–Fab' fragment–conjugating MLs (G250–FMLs) was investigated using the mouse renal cell carcinoma (mRCC) and MN antigen–presenting cell, MN–mRCC. The amount of G250–FMLs uptake reached 67 pg/cell against MN–mRCC cells in an in vitro experiment using plastic dishes and this value was about 6 tunes higher than that in the case of MLs. In an in vivo experiment using MN–mRCC–harboring mice, 1.5 mg of the FMLs per carcinoma tissue accumulated (tumor weight was 0.19 g), which corresponded to approximately 50% of the total injection. This value was 27 tunes higher than that of the MLs. After injection of the FMLs, mice were exposed to intracellular hyperthermia using alternating magnetic field irradiation. The temperature of tumor tissue increased to 43°C and the growth of the carcinoma was strongly arrested for at least 2 weeks. These results indicate the G250–FMLs could target renal cell carcinoma cells in vitro and in vivo, and are efficiently applicable to the hyper thermic treatment of carcinoma.

Surrogate biomarkers of HPV infection in cervical neoplasia screening and diagnosis.

The current prevention of cervical cancer and elimination of its precursors is predicated on the identification of cervical cytologic abnormalities and their histologic confirmation. This strategy, although effective, depends on both sensitivity and specificity of cytology and precise histologic distinction between precursor lesions and their mimics during biopsy interpretation. The effective application of diagnostic criteria is operator dependent and varies as a function of experience and training. However, because human papilloma viruses (HPV) are causative agents and alter the cell cycle in cervical neoplasms, host genes interacting directly or indirectly with HPV oncoproteins have been identified in vitro. Recent research has centered on identifying the host genes upregulated in association with HPV infection, determining their suitability as "surrogate markers" for HPV infection, and using these markers to identify HPV-associated epithelial lesions in tissue or cytologic specimens. This review surveys recent advances in this field, summarizing the advantages and limitations of several candidate biomarkers, including PCNA, Ki-67, cyclin E, p16ink4, MN antigen, carcinoembryonic antigen (CEA), and telomerase in the recognition of preinvasive cervical neoplasia, and discusses their future potential in cervical cancer screening. Based on current studies, the strongest candidates for diagnosis and screening are p16 and cyclin E (squamous) and MN (glandular) biomarkers. As new genes are identified and tested, the concept of biomarkers as tools in primary screening and lesion recognition will continue to mature.

MN antigen expression in normal, preneoplastic, and neoplastic esophagus: A clinicopathological study of a new cancer-associated biomarker

Recently, a novel tumor-associated protein, termed MN, has been described in carcinomas of the uterine cervix, where its expression has been shown to be associated with malignant transformation. Because malignant transformation in the esophagus develops through a dysplasia-carcinoma sequence similar to that which occurs in the cervix, this study was performed to evaluate MN expression in normal, preneoplastic, and neoplastic tissues of the esophagus. Esophageal tumor resection specimens from 27 patients (12 squamous cell carcinomas, one multifocal squamous dysplasia, 10 Barrett's-associated adenocarcinomas, two Barrett's esophagus with dysplasia, two adenosquamous carcinomas) were immunohistochemically stained with a monoclonal antibody (clone M75) directed against the MN antigen. The localization of MN antigen, as well as the proportion of positively stained cells, were determined in sections of normal, dysplastic, and carcinomatous tissues. The staining characteristics were correlated with the pathological features of the tumors. Weak intracellular MN expression was detected only in the basal cells of normal squamous epithelium. However, inflamed and reactive squamous epithelium showed increased staining in the basal layer and in the overlying mature squamous cells. MN expression was significantly increased in dysplastic squamous epithelium ( P < .001). All esophageal squamous cell carcinomas (100%) stained positively for MN antigen, where the pattern of staining was predominantly membranous. However, the degree of MN staining did not correlate with any of the pathological features of the tumors. In Barrett's epithelium, MN stained positively in all types of metaplastic cells and showed no difference in dysplastic epithelium. In contrast to squamous cell carcinomas, only 80% of esophageal adenocarcinomas were positive for MN, but the degree of MN expression was inversely correlated with histological tumor differentiation ( P < .015). The results of this study suggest that (1) the tumor-associated MN antigen may play a role in proliferation and regeneration in esophageal squamous epithelium, and (2) loss of MN expression may be related to cancer progression in Barrett's-associated adenocarcinomas.

A Study of Biomarkers in Cervical Carcinoma and Clinical Correlation of the Novel Biomarker MN

The MN protein is a newly described biomarker found to be overexpressed in most cervical carcinomas. This study was an effort to evaluate the prognostic importance of tumor MN expression, HPV status, and the presence of other biomarkers in cervical cancers. Tumor DNA and protein for study were extracted from archived frozen tissue. Tumor tissues and controls were evaluated by Western blot analysis for MN, intestinal alkaline phosphatase (IAP), c-myc, and p53 protein overexpression. Immunohistochemistry was performed for MN quantification and the study of expression patterns in histologic subtypes of cervical cancer. HPV data were obtained by PCR amplification of extracted DNA using consensus and type-specific primers. Clinical data were obtained from the patients’ records and from the cancer registry. Clinical and molecular data were correlated by χ2, Fisher's exact test, and logistic regression. The results demonstrate that IAP is not overexpressed in clinical specimens of cervical carcinoma, although in somatic cell hybrid experiments, overexpression of IAP correlates with the malignant state. None of 47 tumors, including those which were HPV negative, overexpressed p53. c-myc protein overexpression occurred in 11 of 52 tumors, most of which contained HPV 16, but this was not significantly different from the tumors as a whole. There was no apparent association between MN protein expression and the overexpression of c-myc protein. MN was overexpressed in all cancers and quantitatively varied with the histologic subtype. Specifically, lower expression of MN correlated with adenosquamous and less-differentiated histology (P< 0.01 for grade 3 tumors). Low expression of MN protein also correlated with HPV negativity (P< 0.05). In stage IB and IIA cancers, low expression of MN was associated with deeper cervical stromal invasion (P< 0.03). Further, low expression of MN correlated with lymph node metastases in small (<3.5 cm) IB and IIA cervical cancers (P< 0.04). These data suggest that MN is emerging as a potentially important new biomarker for cervical carcinoma. The overexpression commonly seen in cervical cancer is possibly associated with loss of a critical tumor suppressor gene located on chromosome 11. Low expression of MN antigen appears to correlate with several adverse prognostic features and further prospective study is warranted.

Viral and histopathologic correlates of MN and MIB-1 expression in cervical intraepithelial neoplasia

A recently studied tumor antigen, MN, has been associated with cervical carcinomas and cervical intraepithelial neoplasms (CIN), suggesting that it may serve as a marker for cervical cancer or cancer risk. To determine if expression of the MN antigen paralleled parameters reflecting viral or biological events in precursor epithelium, MN expression was correlated with MIB-1 expression, morphological phenotype, and human papillomavirus (HPV) distribution and type in a series of CINs. Seventy-three percent, 62% and 83% of CIN I, II, and III, respectively, were MN antigen positive. The proportion of neoplastic cells immunoreactive for MN did not correlate with the CIN grade or with HPV types stratified by their association with cancer. Evaluation of serial sections showed no correlation between the frequency of MN antigen staining, the proportion of MIB-1 immunoreactive cells, or the proportion of HPV positive cells detected by in situ hybridization (ISH). CINs associated with prototypical high risk (HPV 16) types exhibited increased immunostaining for the MIB-1 antigen and were more often classified as HSIL in contrast to the other types. Thus, although MN expression previously has been associated strongly with squamous carcinoma, it did not emerge as a specific marker for either cancer-associated HPV types or high grade CIN. CIN I lesions associated with low and high risk HPV types were not distinguished by MIB-1 expression and viral replication. This emphasizes the interrelationship between vegetative viral functions (including viral replication) and morphological phenotype, irrespective of HPV type.

De novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)] with intact blood group-MN locus, confining its locus to 4q28.2–4q31.1

We report a malformed female infant with de novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)]. The MN blood type analysis of the family members showed that the patient had an intact blood group-MN locus. The locus of the gene responsible for the MN antigen activity is confined to a 4q28.2-4q31.1 segment on the basis of the result of this patient and the previous mapping data.

Immunocytochemical determination of ABH and MN antigens on dried blood traces in the nanoliter range

The absorption-elution test and the mixed cell agglutination reaction are both ultimately based on the ability of indicator cells to agglutinate. This agglutination reaction requires a relatively large amount of antigenic epitopes, and, in addition, a relatively high volume of blood traces. The immunocytochemical demonstration of epitopes requires a lower volume, which, however must be fixed for investigation, thus possibly causing damage to the epitopes and thereby preventing detection. An immunocytochemical method is presented which permits ABH and MN antigen determination on dried blood traces of nanoliter quantities without special fixation. This method is based on immunocytochemical demonstration of antigens directly on the cell membrane in combination with the use of a coated glass slide that ensures maximum economy of epitopes.

Number and distribution density of ABH and MN antigen sites on young and old human erythrocyte surfaces

There were no differences in the number of A and M antigen sites between young and old human erythrocyte surfaces. No essential differences in the number of A 1, N and Vicia graminea N antigen sites could be observed between young and old erythrocytes. The number of B and H antigen sites on cell surface was significantly higher in young erythrocytes than in old ones. The distribution density of A and M antigen sites on young erythrocyte was remarkably higher than that on old ones. Compared with young erythrocytes, significant increases in the distribution density of A 1, B, H, N and Vicia graminea N antigen sites were observed in aged erythrocytes. It is suggested from these and other observations that human erythrocytes aging is accompanied by elimination of a small amount of B and H antigens from cell membranes, while A, A 1, M, N and Vicia graminea N antigens are not released from cell membranes during in vivo aging.

Pj variant, a new hybrid MNSs glycoprotein of the human red-cell membrane.

An unusual glycoprotein variant (Pj) was found inherited through a caucasian family exhibiting atypical N and Nvg blood-group reactivities. Pj erythrocytes are blood-group-MS homozygous and have a normal sialic acid content. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis the variant contains a new component Pj of 24kDa apparent molecular mass in the monomeric state which is sharply stained by periodic acid/Schiff reagent. Both blood-group-MN (alpha) and -Ss (delta) glycoproteins were present. Homodimers (Pj2) as well as heterodimers with MN-glycoprotein (alpha Pj) and the Ss-glycoprotein (delta Pj) were also identified. The new sialoglycoprotein Pj is trypsin- and chymotrypsin-resistant in situ and carries N- and Nvg- but not M- and S-reactivities. The Pj component is labelled by lactoperoxidase-catalysed radioiodination. A 3H label is also easily introduced into the sialic acid or the galactose and galactosamine of the Pj glycoprotein. It is proposed that the Pj is a hybrid glycoprotein containing the N-terminal end of delta-glycoprotein and the C-terminal end of the alpha-glycoprotein. This proposal is supported by the finding that Pj carries a leucine residue at its N-terminus and is not immunoprecipitated by a monoclonal mouse antibody (R18) reacting specifically with the external domain of glycoprotein alpha. The red cells from the proposita Pj were found positive for a very low frequency MN antigen named Sta.

Delayed-type skin hypersensitivity reaction (DTH) to thomsen-friedenreich (T) antigen as diagnostic test for human breast adenocarcinoma

One intradermal (i.d.) injection of human erythrocyte T antigen in the upper outer arm contralateral to any breast lesion elicits a delayed tuberculin-type hypersensitivity reaction (DTH) in breast carcinoma patients. It is necessary to inject simultaneously but separately the same quantity of MN antigen (about 6--8 cm apart), from which the T Antigen has been prepared, since particularly patients with Stage I breast carcinoma (Internatl. nomenclature) and those with benign breast disease may significantly react to it. The extent of reaction to MN antigen must be subtracted from the reaction to T antigen before interpreting results. DTH response to T antigen was 85% accurate among 67 patients with ductal breast carcinoma of all Stages (including non-invasive), 95% accurate (5% so far falsely positive) among 95 patients with benign breast disease and it was 100% accurate (no false positives) among 36 "healthy" persons tested. Among 18 patients with the comparatively rare and less ominous lobular and tubular breast carcinomata, the DTH reaction was positive in 8 of 16 (50%) patients with lobular, and in none of 2 patients with tubular breast carcinoma.

Anti-N in the serum of a healthy type MN person--a further example.

A healthy, type MN, Caucasian woman, with no evidence of a subgroup of N or autoimmune disease, was found to have anti-N and strong anti-H in her serum. The anti-H in a sample of blood taken after delivery of her fourth child was strong enough to mask the anti-N at 22 C, whereas in pre-delivery samples it had been very weak. The case is similar to one reported by Metaxas- Biihler and associates2 in 1961, and another by Greenwalt and colleagues1 in 1966. A family study is presented, and the MN antigen is investigated in detail. The reason for the phenomenon remains unexplained.