Yuko Kikuchi

Serologic dissection of HLA-D specificities by the use of monoclonal antibodies

To study the gene products of theHLA complex, we produced two monoclonal antibodies, termed HU-18 and HU-23. They were active in complement-dependent cytotoxicity and detected B-cell alloantigens encoded by a locus (or loci) linked toHLA. When three types of HLA-DR4 homozygous B-cell lines with different HLA-D specificities were tested for reactivity with HU-18 and HU-23, they displayed distinct reaction patterns depending on the HLA-D specificities they possessed: EBV-Wa (HLA-DYT homozygous), negative for both HU-18 and HU-23; KT2 and KOB (HLA-DKT2 homozygous), positive only for HU-18; and ER (HLA-Dw4 homozygous), positive for both. These differential reaction patterns were further confirmed by testing against a panel of 17 HLA-DR4-positive peripheral blood lymphocytes with known HLA-D specificities. Thus, these monoclonal antibodies allow us to identify HLA-DYT, HLA-DKT2, and HLA-Dw4 solely by serologic methods. This is the first clearcut serologic identification of these three HLA-DR4-associated HLA-D specificities, which have been indistinguishable by conventional serology and identified only by cellular techniques. It is hoped that immunochemical investigations using HU-18 and HU-23 will advance our understanding of theHLA-D region on a molecular level.

PRIMARY YOLK SAC TUMOR OF THE LIVER

An autopsy case of yolk sac tumor of the liver in a 29‐year‐old female was reported. The tumor was found originally in the right anterior segment of the liver on the first operation. The autopsy disclosed that the liver was almost entirely replaced by multiple, round tumor nodules. The tumor masses continuously extended to the peritoneum and to the subcutaneous tissue. There were no tumors in other organs including the ovaries, gut, stomach, lung, uterus, and kidneys, indicating that the tumor originated in the liver. Microscopically, the tumor showed typical characteristics of the yolk sac tumor. An immunohistochemical study showed that AFP was distributed fine granularly in the cytoplasm of tumor cells. Electron microscopic observation disclosed large amounts of electron‐dense material being closely related to basement membrane.

Evidence for polymorphism of MB3 antigens among three HLA-D clusters associated with HLA-DR4

In a previous study, we showed that the three hitherto serologically indistinguishable HLA-D specificities associated with HLA-DR4, HLA-DYT, HLA-DKT2, and HLA-Dw4 can be distinguished on the basis of their reactivity with two distinct la-like-specific monoclonal antibodies, HU-18 and HU-23. In this study, we attempted to identify and characterize Ia-like molecules recognized by HU-18 and HU-23 on a molecular level because la subsets (HLA-DR, MB, MT, or SB) identified by them remained unknown. The results of sequential coprecipitation assays and two-dimensional gel analyses showed that both HU-18 and HU-23 recognize antigenic determinants borne on M133 but not on HLA-DRw6.2 molecules. Because the two monoclonal antibodies, specific for determinants carried on MB3 molecules, show distinct reactivity against homozygous typing cells defining HLA-DYT, HLA-DKT2, and HLA-Dw4, all of which share DR4-MB3, the data indicate that these three HLA-D clusters associated with HLA-DR4 possess distinct MB3 molecules, suggesting the existence of polymorphism in MB3 antigens.

A Study on Class II Antigens Involved in the T Cell Prorliferative Responses to PPD Using Cross-Reacting Monoclonal Antibodies in Human and Murine System

Two monoclonal antibodies (MoAb) 1E4 and ISCR3, which detect class II antigens across species barriers, were studied for their inhibitory effects on human and murine T cell proliferative responses to purified protein derivative of tuberculin (PPD). The 1E4 detected at least a polymorphic determinant on I-A molecules from mice carrying the H-2b haplotype, and the ISCR3 detected the Ia.7 determinant on I-E molecules. Nevertheless, both 1E4 and ISCR3 recognized monomorphic determinants on HLA-DR antigens (human I-E equivalent molecules), but not on HLA-DQ antigens (human I-A equivalent molecules). It was demonstrated that 1E4 significantly inhibited PPD-specific responses of T cells from Ib-bearing mice. In contrast, ISCR3 showed marginal effects on the responses of mice bearing Ia.7. However, in the human system both 1E4 and ISCR3 reduced proliferative responses to PPD. These results suggest that a functional difference exists between humans and mice in the I subregion products involved in the T cell proliferative responses to PPD.

CHORIOCARCINOMA OF THE ESOPHAGUS PRODUCING CHORIONIC GONADOTROPIN

An autopsy case of primary esophageal choriocarcinoma in a 42‐year‐old Japanese male Is reported. The tumor was pure choriocarcinoma typical hemorrhagic and necrotic nature occupying almost the entire circumference of the mid‐esophagus. The choriocarcinoma had metastasized to the liver, lung and lymph nodes. In the esophageal tumor, immunohistochemical staining showed the presence of mainly human chorionic gonadotropin (HCG), with human placental lactogen (HPL) in a few syncytiotrophoblastic cells. Only 3 cases of extragonadal choriocarcinoma originating in the esophagus have been reported up to now. The possible pathogenesis and pathological characteristics of primary esophageal choriocarcinoma are discussed.

Long arm deletion of the X chromosome, 46,X,del(X)(q21), associated with gonadoblastoma

SummaryA 28-year-old woman with short stature was found to have bilateral gonadoblastoma in the dysgenetic ovaries. Chromosome banding analysis of her cultured blood cells and skin fibroblasts revealed a terminal deletion of the long arm of the X chromosome, 46,X,del(X)(q21), as the sole karyotypic anomaly. None of the Xq- patients so far reported were associated with gonadoblastoma.

THE B REGION‐ASSOCIATED ANTIGENS AND MLR PHENOTYPES IN THE JAPANESE INBRED STRAINS OF RATS

Seven different alloantisera absorbed with red blood cells (RBC) from appropriate strains of rats detected a series of B cell alloantigenic specificities that could be divided into two groups, presumably coded for by at least two different closely‐linked loci in the rat major histocompatibility complex (MHC), RT1. The one locus had two allele codes for a broad specificity and the other locus codes for a unique specificity that was found only in the restricted strains of rats that shared the same mixed lymphocyte reaction (MLR) phenotype. RBC‐absorbed alloantisera were monitored against a panel of B cell fractions obtained from sixteen inbred strains. Two alloantisera, ACI anti‐W and W anti‐TO detected two broad specificities, into either of which all inbred strains tested were classified. Two broad RT1‐B region‐associated specificities were thus designated provisionally as Ba‐1.1 and ‐1.2. Another five alloantisera detected four respective specificities which have a narrower strain distribution. Sixteen inbred strains were classified into one of five specificities detected by W anti‐F344, F344 anti‐SDJ, WKA anti‐ACI, W anti‐BUF and ACI anti‐W absorbed with LEJ lymph node cells. Each specificity was designated provisionally as Ba‐2.1, ‐2.2, ‐2.4, ‐2.6, ‐2.7, respectively. A complete association of Ba‐2 specificities with MLR phenotype was observed. Antigenic specificities of Ba‐2.1, ‐2.2 and ‐2.4 were all classified in a group of Ba‐1.1 specificity, whereas Ba‐2.6 and ‐2.7 specificities were associated with Ba‐1.2 specificity. This relationship suggested a linkage disequilibrium between the two loci for the Ba antigens.

Three monoclonal antibodies specific for human class II antigens detect RT1B-linked polymorphisms in rat B cells.

Three monoclonal antibodies HU‐11, HU‐32, and HU‐33, which recognize two distinct polymorphic determinants of human class II antigens, were found to cross‐react with rat B cells carrying an RT1B region‐associated specificity Ba‐2.6. This is the first report demonstrating that xenoimmune antibodies raised against polymorphic determinants of human class II antigens are able to detect polymorphic determinants of class II antigens in a third party species.