Distribution and migration pathways of HNK-1-immunoreactive neural crest cells in teleost fish embryos.

Whole mounts and cross-sections of embryos from three species of teleost fish were immunostained with the HNK-1 monoclonal antibody, which recognizes an epitope on migrating neural crest cells. A similar distribution and migration was found in all three species. The crest cells in the head express the HNK-1 epitope after they have segregated from the neural keel. The truncal neural crest cells begin to express the epitope while they still reside in the dorsal region of the neural keel; this has not been observed in other vertebrates. The cephalic and anterior truncal neural crest cells migrate under the ectoderm; the cephalic cells then enter into the gill arches and the anterior truncal cells into the mesentery of the digestive tract where they cease migration. These cephalic and anterior trunk pathways are similar to those described in Xenopus and chick. The neural crest cells of the trunk, after segregation, accumulate in the dorsal wedges between the somites, however, unlike in chick and rat, they do not migrate in the anterior halves of the somites but predominantly between the neural tube and the somites, the major pathway observed in carp and amphibians; some cells migrate over the somites. The HNK-1 staining of whole-mount embryos revealed a structure resembling the Rohon-Beard and extramedullary cells, the primary sensory system in amphibians. Such a system has not been described in fish.     

Immunocytochemical developmental patterns of the thoracolumbar sympathetic chain in the chick and a comparison with its adrenal counterpart

The immunocytochemical development of the thoracolumbar sympathetic ganglion and its adrenal counterpart was studied in the chick from days 3.5 to 12 of incubation, using antibodies to 17 separate antigens, including antibodies to pan-neuroendocrine markers, catecholamine-synthesizing and proprotein-processing enzymes, and neuropeptides. Some of the antigens studied (Go protein-alpha subunit, thyrosine hydroxylase, and galanin) were strongly expressed from the first days of development, whereas others (chromogranin-A, chromogranin-B, 7B2 protein, and somatostatin) showed a diverse immunoreactive expression at different stages. Three different patterns were found in the development of both adrenal medulla and thoracolumbar sympathetic ganglion. In the first (chromogranin-A and B, Go protein-alpha subunit, tyrosine hydroxylase, HNK-1, and galanin), virtually all medullary and thoracolumbar sympathetic ganglion cells were strongly immunostained from day 4 onward. Except for HNK-1, chromogranin-A and B, there was a steady increase in immunoreactive cells for all the remaining antigens up to day 12. In the second (7B2 protein, proprotein convertase 2, and secretogranin II), full antigenic expression was reached in medullary and thoracolumbar sympathetic ganglion cells by day 10. In the third pattern (proprotein convertase 3, somatostatin, dopamine-beta-hydroxylase, neuron-specific enolase, vasoactive intestinal polypeptide, and met-enkephalin), differences in immunoreactivity were observed between the medullary and thoracolumbar sympathetic ganglion cells.     

Developmental Expression of HNK-1-Reactive Antigens in Rat Cerebral Cortex and Molecular Heterogeneity of Sulfoglucuronylneolactotetraosylceramide in CNS Versus PNS

Monoclonal antibody HNK-1 reacts with a carbohydrate epitope present in proteins, proteoglycans, and sulfoglucuronylglycolipids (SGGLs). On high-performance TLC plates, SGGLs of the CNS from several species migrated consistently slower than those from the PNS, a result indicating possible differences in the structures. The structural characteristics of the major SGGL, sulfoglucuronylneolactotetraosylceramide (SGGL-1), from CNS was compared with those of SGGL-1 from PNS. Although the composition, sequence, and linkages of the carbohydrate moiety of the SGGL-1 species were identical, SGGL-1 from CNS contained mainly short-chain fatty acids, 16:0, 18:0, and 18:1, amounting to 85% of the total fatty acids, whereas SGGL-1 from PNS contained large proportions (59%) of long-chain fatty acids (greater than 18:0). These differences in the fatty acid composition accounted for the different migration pattern observed. The developmental expression of SGGLs and HNK-1-reactive proteins was studied in rat cerebral cortex between embryonic day (ED) 15 to adulthood. SGGLs in the rat cortex were maximally expressed around ED 19 and almost completely disappeared by postnatal day (PD) 20. This expression was contrary to their increasing expression in the cerebellum and sciatic nerve with postnatal development. Six to eight protein bands with a molecular mass of greater than 160 kDa were HNK-1 reactive in the rat cerebral cortex at different ages. The major HNK-1 reactivity to the 160-kDa protein band seen in ED 19 to PD 10 cortex decreased and completely disappeared from the adult cortex, whereas several other proteins remained HNK-1 reactive even in the adult. Western blot analyses of the neural cell adhesion molecules (N-CAMs) during development of the rat cortex with a polyclonal anti-N-CAM antibody showed that the major HNK-1-reactive protein bands were not N-CAMs. Between PD 1 and 10, 190-200-kDa N-CAM was the major N-CAM, and between PD 15 to adulthood, 180-kDa N-CAM was the only N-CAM present in the rat cortex.     

The spatial and temporal expression of HNK-1 by myogenic and skeletogenic cells in the embryonic rat

The existence of phenotypic differences within a population of cells provides evidence for discrete stages in cellular differentiation and/or identifies subsets of cells with unique functional properties. The monoclonal antibody HNK-1 has been widely shown to identify subpopulations of cells in the developing nervous system. In this paper we focus on the developmental expression of HNK-1 immunoreactivity by derivatives of somitic (paraxial) mesoderm. We show that between embryonic day 12 and 14 (E12–E14) the HNK-1 epitope is transiently expressed by postmitotic myotomal cells. In E14–E17 developing vertebral columns (which are derived from somitic sclerotomal cells), HNK-1 immunolabeling was expressed by subpopulations of skeletogenic cells, including perinotochordal cells associated with the forming annulus fibrosus and cells within or adjacent to the perichondrium. Chondrocytes within forming centra and vertebral arches did not exhibit HNK-1 immunoreactivity. These results, taken together, show that the expression of the HNK-1 epitope can be used to identify subsets of myogenic and skeletogenic cells both spatially and temporally in the developing rat.     

Electron microscopy of neurosecretory nerve fibres in the neural lobe of the embryonic mouse

Summary Nerve fibres of the neurosecretory hypothalamo-hypophyseal tract were studied in embryonic C3H mouse neural lobes; at least four glands at each gestational day 15–19 were examined.Single axons and small bundles of fibres are visible at gestational days 15 and 16. By day 17 large fibre bundles penetrate between glial cells. They increase in number during the next two days.Electron-lucent and electron-dense vesicles are seen in the fibres of the 15th and 16th gestational days. In the 17–19 day-old embryos development is characterized by a successive rise in the number of the two types of vesicles. The mean diameter of the electron-lucent vesicles is approximately unchanged in all the stages examined (50 nm). The electron-dense vesicles increase in size from approximately 80–90 nm at days 15–16 to 140 nm at the 19th gestational day.By day 19 contacts between neurosecretory fibre terminals and the outer basement membrane of internal and peripheral capillaries are occasionally observed. The possibly adrenergic nature of a few terminals contacting peripheral vascular structures in 17 and 18 day-old embryos is suggested.This investigation was supported by grant No. 2180-020 from the Swedish Natural Science Research Council. The skilful technical assistance of Mrs. Ulla Wennerberg is gratefully acknowledged.     

80％门静脉结扎后肝脏组织中MMP-9的表达与肝再生作用的相关性研究

目的：探讨基质金属蛋白酶-9（MMP-9）在大鼠80％门静脉分支结扎模型中大鼠增生肝脏组织中的表达及其与肝再生作用的关系。方法：健康SD雄性大鼠48只,随机平均分成假手术对照组（Sham）和门静脉结扎实验组（PVL）。观察术后1、3、7和14d保留侧肝叶重量／体重比值;下腔静脉采血后检测血清谷丙转氨酶（ALT）、谷草转氨酶（AST）值的变化;光镜下观察保留侧肝脏组织的病理形态变化;用免疫组化法检测增殖细胞核抗原（Proliferating cell nuclear antigen,PCNA）的表达,用免疫印记法检测MMP-9的表达,并进行统计分析。结果：80％门静脉分支结扎后,结扎侧肝叶呈进行性萎缩,保留侧肝叶重量／体重比值逐渐增加,7d达“平台期”;与对照纽明显不同,PVL组的ALT、AST的值在1h达到高峰,7d后回到正常水平;保留侧肝脏组织中PCNA阳性细胞计数与对照组比较,3d开始表述增强（P〈0．05）,7d以后逐渐恢复至正常水平（P〉0．05）;保留侧肝叶MMP-9蛋白的表达在术后3d开始增加,术后7d达到高峰。结论：MMP-9蛋白的表达在80％门静脉结扎后大鼠肝再生过程中发挥重要作用。     

移植途径对大鼠骨髓间充质干细胞归巢及肝功能恢复的影响

目的 探讨移植途径对骨髓间充质干细胞（MSCs）归巢及促进肝切除大鼠肝再生的影响.方法 建立肝切除大鼠模型,随机分为3 组,即肝切除对照组、尾静脉移植组和门静脉移植组.移植组分别经尾静脉和门静脉注射DAPI 标记的MSCs 约1.5×106/ 只,分别于第3 天和第9 天后采血清检测肝功能,第9 天处死大鼠取肝脏标本,并通过荧光显微镜观察两种移植途径对MSCs 向肝脏迁移的影响.结果 门静脉移植组（18.1 ± 3.4）个细胞/100 倍视野到肝脏归巢及定植的 MSCs 多于尾静脉移植组（7.6 ± 2.0）个细胞/100 倍视野,差异有统计学意义（P 〈 0.01）.术后第9 天各组大鼠肝功能均有好转,丙氨酸氨基转移酶（ALT）及天冬氨酸氨基转移酶（AST）3 组之间对比差异无统计学意义（F = 2.822,1.046,P = 0.057,0.365,P 〉 0.05）;但两移植组与单纯肝切除组比较血浆白蛋白（ALB）均有明显升高,差异具有统计学意义（F = 6.259,P = 0.006）;尾静脉移植组与门静脉移植组两移植组之间相比,差异无统计学意义（P 〉 0.05）.结论 移植途径对 MSCs 归巢、定植到肝脏有一定影响,门静脉途径优于外周静脉,MSCs 移植对肝大部切除大鼠肝功能恢复具有促进作用.     

Characterization of a Sulfoglucuronyl Carbohydrate Binding Protein in the Developing Nervous System

Abstract: The developmentally regulated and stage-specifically expressed HNK-1 carbohydrate found on sulfoglucuronylglycolipids (SGGLs) and certain glycoproteins has been proposed to be involved in neural cell adhesion and recognition processes through its interaction with protein "receptors." We have isolated and purified a ∼30-kDa SGGL-binding protein (SBP-1) from neonatal rat brain. SBP-1 specifically bound to SGGLs and sulfatide both in solid-phase immunobinding and high-performance thin-layer chromatography-immunooverlay assays. N-terminal sequence analysis showed that SBP-1 is similar to an adhesive neurite outgrowth promoting protein amphoterin. Desulfation of SGGLs resulted in abolition of SBP-1 binding. However, chemical modification of glucuronic acid moiety by either esterification or reduction of the carboxyl group had no effect, suggesting requirement of the carbohydrate-linked sulfate group for SBP-1 binding. The binding of SBP-1 to SGGLs was specifically inhibited by HNK-1 antibody but not by other IgM antibodies. The binding of SBP-1 to sulfatide, however, was not inhibited by HNK-1 antibody. Heparin, fucoidan, and dextran sulfate (50K) also inhibited the binding of SBP-1 to SGGLs. During development of the rat cerebral cortex, the level of SBP-1 decreased after embryonic day 18 to an almost undetectable level by postnatal day 10; whereas in the cerebellum, the expression of SBP-1 was maximal at postnatal day 7. SBP-1 also bound specifically to the HNK-1 glycoproteins isolated from rat brain by HNK-1 immunoaffinity chromatography. Proteins without HNK-1 carbohydrate did not bind SBP-1. The binding to HNK-1 glycoproteins was inhibited by HNK-1 antibody, but not by other IgM antibodies, indicating that the binding was mediated through the HNK-1 carbohydrate moiety of the proteins. The interaction and coexpression of SBP-1 with SGGLs and HNK-1 glycoproteins, during the perinatal brain development, suggest a functional role for this protein.     

Development of the digestive tract in larval summer flounder

Histological changes of the digestive system and its associated glands, and structures of the jaw were studied in summer flounder Paralichthys dentatus from hatching (day 0) until day 44. Specimens for this study were hatched from artificially spawned broodstock and maintained in the laboratory (20 ± 1° C). During the first 3 days after hatching, the formation of the oral jaw apparatus, lengthening of the digestive tube, yolk resorption, and mucosae differentiation are the most conspicuous elements of development. The larval digestive system is morphologically ready to process external food at the time of mouth opening (3–4 days after hatching). Epithelial cells of the anteromedian and the posterior intestine show evidence of lipid and protein absorption, respectively, after first feeding. The most noticeable events occurring during the next month of independent life are an increase in mucosal folding, cellular differentiation in the luminal epithelia, gut segmentation and looping, and liver growth. Gastric glands and pyloric caeca appear by day 31 and complete the morphological digestive features characteristic of the juvenile stage.     

Quantitative changes in the frequency and distribution of the C-cell population in the rat thyroid gland with age

Summary The development of calcitonin cells (C-cells) was investigated in rat thyroid glands from birth to 120 days, using an immunoperoxidase technique and a point-counting method. The proportion of C-cells to follicular cells was 4.5% on the day of birth and increased progressively to 10.4% by 120 days. The highest density of C-cells was noted in the mid-region of the lobes along a longitudinal axis. The caudal and cephalic regions of the lobes contained smaller numbers of C-cells. The C-cells tended to be more numerous in the posterior aspects of the lobes. Although the numbers of C-cells in 120-day-old animals were markedly increased as compared to animals at the time of birth, the cell distributions within the glands were similar at all ages.     

Immunohistochemical detection of hypoxia in mouse liver tissues treated with pimonidazole using “in vivo cryotechnique”

To evaluate hypoxic cells in live mouse liver tissues, immunohistochemistry for protein adducts of reductively activated pimonidazole (PARaPi) was performed using the “in vivo cryotechnique (IVCT)” followed by freeze-substitution fixation. This method was used because cryotechniques have some merits for examining biological events in living animal organs with improved time-resolution compared to conventional perfusion and/or immersion chemical fixation. Pimonidazole was intraperitoneally injected into living mice, and then after various times of hypoxia, their livers were quickly frozen by IVCT. The frozen liver tissues were freeze-substituted in acetone containing 2% paraformaldehyde, and routinely embedded in paraffin wax. De-paraffinized sections were immunostained for PARaPi. In liver tissues of mice without hypoxia, almost no immunostained cells were detected. However, in liver tissues with 30 s of hypoxia, some hepatocytes in the pericentral zones were strongly immunostained. After 60 s of hypoxia, many hepatocytes were immunostained with various degrees of staining intensity in all lobular zones, indicating different reactivities of pimonidazole in the hepatocytes to hypoxia. At this time, the general immunoreactivity also appeared to be stronger around the central veins than other portal areas. Although many hepatocytes were immunostained for PARaPi in the liver tissues with perfusion fixation via heart, those with perfusion via portal vein were not immunostained. Thus, IVCT is useful to detect time-dependent hypoxic states with pimonidazole treatment in living animal organs.     

Substance P and neurokinin A immunoreactive nerve fibres in the developing salivary glands of the rat

The time of appearance and distribution of substance P (SP) and neurokinin A (NKA) immunoreactive nerve fibres in developing salivary glands of the rat were studied by the use of indirect immunohistochemical methods. The glands were examined at daily intervals from the 15th day in utero (i.u.) until birth, and subsequently on the 2nd, 5th, 7th, 12th, 16th and 30th postnatal day. The findings were compared to samples from adult. The first SP- and NKA-immunoreactive (IR) nerve fibres appeared on the 19th day i.u. in the parotid and submandibular glands and were abundantly distributed around developing ductal branches. In the mesenchyme around the developing ductal branches of the parotid gland the fibres appeared on the 20th day i.u. In the submandibular gland NKA-IR fibres appeared in the mesenchyme surrounding the developing ductal branches on the 19th day i.u. and SP-IR fibres on the 21st day i.u. Around blood vessels of both glands, SP- and NKA-IR fibres made their appearance only much later, on the second postnatal day. The number of SP- and NKA-IR nerve fibres in the developing salivary glands was already high on the 19th day i.u. when they were first detected. From this point up to the 16th postnatal day the glands were richly innervated by the fibres, but later the numbers slowly decreased to adult levels. The abundance of SP- and NKA-IR nerve fibres especially around the ductal branches and secretory structures in the developing salivary glands suggests a role in the functional maturation of salivary glands.     

脉红螺消化系统的形态学研究

脉红螺消化系统由十二个器官组成。其消化管壁都由粘膜层、粘膜下层、肌层和外膜四层结构构成。作者对消化腺的细胞进行了较详细的描述,并利用组化方法测定消化腺细胞中含有的酶类。作者还对部分器官的超微结构进行了观察。     

Substance P and neurokinin A immunoreactive nerve fibres in the developing salivary glands of the rat.

The time of appearance and distribution of substance P (SP) and neurokinin A (NKA) immunoreactive nerve fibres in developing salivary glands of the rat were studied by the use of indirect immunohistochemical methods. The glands were examined at daily intervals from the 15th day in utero (i.u.) until birth, and subsequently on the 2nd, 5th, 7th, 12th, 16th and 30th postnatal day. The findings were compared to samples from adult. The first SP- and NKA-immunoreactive (IR) nerve fibres appeared on the 19th day i.u. in the parotid and submandibular glands and were abundantly distributed around developing ductal branches. In the mesenchyme around the developing ductal branches of the parotid gland the fibres appeared on the 20th day i.u. In the submandibular gland NKA-IR fibres appeared in the mesenchyme surrounding the developing ductal branches on the 19th day i.u. and SP-IR fibres on the 21st day i.u. Around blood vessels of both glands, SP- and NKA-IR fibres made their appearance only much later, on the second postnatal day. The number of SP- and NKA-IR nerve fibres in the developing salivary glands was already high on the 19th day i.u. when they were first detected. From this point up to the 16th postnatal day the glands were richly innervated by the fibres, but later the numbers slowly decreased to adult levels. The abundance of SP- and NKA-IR nerve fibres especially around the ductal branches and secretory structures in the developing salivary glands suggests a role in the functional maturation of salivary glands.     

Development of substance P and neurokinin A immunoreactivity in ganglia supplying nerves to the submandibular glands of the rat

Developing submandibular, trigeminal and superior cervical ganglia, which provide innervation to the submandibular glands, were studied for substance P (SP)-and neurokinin A (NKA)-immunoreactive (IR) ganglion cells and nerve fibres in rat. These ganglia were examined by using an indirect immunofluorescence technique at daily intervals from the 16th day in utero (i.u.) until birth, and subsequently on the 2nd, 5th, 7th, 12th, 16th, 30th, 42nd postnatal day and in the adult (3 months). In the submandibular ganglion SP- and NKA-IR cells and fibres first appeared in considerable numbers on the 19th day i.u. (in one sample out of five on the 18th day i.u.), when more than 90% of the ganglion cells were immunoreactive to SP and NKA. The number stayed at more than 90% to the 7th postnatal day and then slowly decreased to the levels of adult animals (18% SP, 17% NKA). The first SP- and NKA-IR ganglion cells and fibres appeared in the trigeminal ganglion on the 18th day i.u. when they represented 7% (SP) and 4% (NKA) of the ganglion cells. The number of SP- and NKA-IR cells increased steadily, reaching a maximum at the time of birth when 68% (SP) and 74% (NKA) of the ganglion cells were immunoreactive. Thereafter they began to decrease toward the level of an adult rat (10% SP, 11% NKA). In the superior cervical ganglion only a few SP-and NKA-IR ganglion cells were detected from the 19th day i.u. to the fifth postnatal day. Positive ganglion cells were also occasionally found in the nerve trunks outside the superior cervical ganglion. From the seventh day onwards no SP- or NKA-IR ganglion cells were found. SP-and NKA-IR SIF (small intensively fluorescent) cells were detected from the 16th postnatal day onwards.     

Colonization of the rat liver by syngeneic tumor cells. An experimental approach by in vivo and in situ studies

Syngeneic colon carcinoma cells and glioma cells were injected into the portal vein of BD IX rats. After various time periods the animals were sacrificed and the livers and lungs were fixed and prepared for histology. Atypical cells were observed in the liver 4 and 7 days after the injection of tumor cells, whereas distinct colonies of both colon carcinoma and glioma cells were demonstrated after 14 days. Lung metastases of both tumor cell types were seen after 14 and 30 days. Furthermore, injection of glioma and carcinoma cells into the tail vein gave detectable lung metastases after 7 and 4 days respectively. Intraperitoneal injection of tumor cells resulted in the accumulation of large tumor masses, particularly in the mesentery. By in situ perfusions of the liver with tumor cells included in the perfusion medium it was possible to establish that all the tumor cells were arrested in the course of 4 min. In contrast, normal rat leukocytes were not trapped in the liver, whereas trypsin-treated leukocytes were, suggesting the importance of trypsin-sensitive structures for binding to hepatic tissue. The binding of both glioma and carcinoma cells to the liver and the ensuing growth of tumor nodules in this organ indicate a lack of specificity on part of the malignant cell types for metastasis to the liver in the rat. Both tumor cell types colonized the first organ encountered after injection.     

Morphology of the digestive system in carnivorous freshwater dourado Salminus brasiliensis

The digestive system of teleost shows remarkable functional and morphological diversity. In this study, the digestive tract and accessory organs of dourado Salminus brasiliensis are characterized using anatomical, histological, histochemical and immunohistochemical analyses. The existence of taste buds bordered by microridges in the oesophagus of dourado was recorded for the first time, thus showing that the species drives food intake by either swallowing or rejecting the food item. The Y-shaped stomach of dourado consisted of cardiac, cecal and pyloric regions with tubular gastric glands registered solely in the cardiac and cecal segments. The intestine is a short N-shaped tube with two loops, an intestinal coefficient of 0.73. The structure of pyloric caeca is similar to that of the intestine wall, comprising tunica mucosa, tela submucosa, tunica muscularis and tunica serosa layers. Histochemical analyses revealed an increased incidence of goblet cells from the midgut to the hindgut segment. A well-developed enteric plexus of scattered nerve cell and fibres are found along the digestive tract, and the calcitonin gene-related peptide (CGRP) immunoreactive neurons and fibres were identified in the myenteric plexus from the oesophagus to the hindgut. The exocrine pancreas appears diffuse in the mesentery around the stomach, intestine and also reaches the liver, and the endocrine pancreas is organized as a few islets of Langerhans. The liver comprises three distinct, asymmetric lobes, and the portal triad arrangement was registered in this tissue.     

Origin and development of VIP and substance P containing neurons in the embryonic avian gut

The development of substance P (SP) and VIP containing structures of the quail and chick guts was studied by immunocytochemistry. The appearance of VIP and substance P nerves follows a rostrocaudal pattern from day 9 in the quail and day 10 in the chick embryo. Immunoreactive fibres are first visible in the oesophagus and at 12 days they extend over the whole length of the intestine. VIP and substance P ganglionic cells are first localized in the foregut (day 9 for VIP containing neurons and day 13 for SP ones) and observed in the mid- and hind-gut just before hatching. Transplantation on the chorioallantoic membrane (CAM) of fragments of various parts of the digestive tract were carried out to see whether in such circumstances the pattern of VIP and SP containing nerves was comparable to normal. The explants contained numerous SP and VIP immunofluorescent nerve fibres. In addition, cell bodies with VIP and SP immunoreactivity appeared brightly fluorescent in the enteric ganglia of the graft showing that these peptidergic nerve cells belong to the intrinsic innervation of the gut.     

Origin and development of VIP and substance P containing neurons in the embryonic avian gut

Summary The development of substance P (SP) and VIP containing structures of the quail and chick guts was studied by immunocytochemistry. The appearance of VIP and substance P nerves follows a rostrocaudal pattern from day 9 in the quail and day 10 in the chick embryo. Immunoreactive fibres are first visible in the oesophagus and at 12 days they extend over the whole length of the intestine. VIP and substance P ganglionic cells are first localized in the foregut (day 9 for VIP containing neurons and day 13 for SP ones) and observed in the mid- and hind-gut just before hatching. Transplantation on the chorioallantoic membrane (CAM) of fragments of various parts of the digestive tract were carried out to see whether in such circumstances the pattern of VIP and SP containing nerves was comparable to normal. The explants contained numerous SP and VIP immunofluorescent nerve fibres. In addition, cell bodies with VIP and SP immunoreactivity appeared brightly fluorescent in the enteric ganglia of the graft showing that these peptidergic nerve cells belong to the intrinsic innervation of the gut.     

Characterization of HNK-1+ (Leu-7) human lymphocytes: III. Interferon effects on spontaneous cytotoxicity and phenotypic expression of lymphocyte subpopulations delineated by the monoclonal HNK-1 antibody

Interferon (IFN) augments the cytotoxic function of natural killer (NK) and killer (K) cells. We have previously shown that all NK- and K-cell function resides in the HNK-1⁺ population of granular lymphocytes. The present experiments demonstrated that IFN significantly augmented the efficiency of purified HNK-1⁺ cells to perform both NK- and K-cell function. In contrast, HNK-1^? cells could not lyse target cells even in the presence of IFN. IFN did not generate new HNK-1⁺ cells from the pool of HNK-1^? cells. We then examined the possibility that IFN might induce the maturation of immature NK cells previously defined as having an HNK⁺T3⁺ phenotype and a paucity of cytoplasmic granules. However, no changes were observed either in the proportion of HNK-1⁺ cells expressing the T3 antigen or in the number of granules within each HNK-1⁺ cell even after an 18-hr incubation with IFN. While fresh HNK-1^? cells lack NK-cell function, they can acquire NK-like activity without expressing the HNK-1 antigen after incubation with either alloantigens or mitogens. When incubated further with IFN, these alloantigen- or PHA-activated HNK-1^? cells with NK-like activity demonstrated relatively little augmentation of their cytotoxicity. It is concluded that interferon exerts its influence on restricted subpopulations of cells, primarily HNK-1⁺ cells. Its mechanism appears to concern the cytotoxic event rather than influencing cellular maturation.