Onchocera volvulus: characterization of a highly immunogenic Gln-rich protein

A pool of sera from individuals classified as putatively immune (PI) to Onchocerca volvulus infection was employed in the screening of a fourth-stage larval cDNA expression library. A highly immunogenic clone, encoding the Ov 53/80 protein, was identified. The full length cDNA of clone 4.21 contained 2527 nucleotides encoding 769 amino acids of which 100 are glutamine residues (13%). Antibodies raised against recombinant protein encoded by a partial cDNA sequence (clone 73-k) recognized a 53 and 80 kDa protein in O. volvulus larval and adult parasite extracts, respectively. The antibodies localized the native protein in the cuticle, hypodermis, secretory vesicles and in granules of the glandular esophagus of larvae and in the hypodermis and the cuticle of adult worms. The recombinant 73-k polypeptide (r73) was recognized by 90-100% of sera from PI and infected individuals from Liberia, but only by 67% of similar groups from Ecuador. r73 specific IgG2 and IgG3 levels in the PI from Liberia and Ecuador, respectively, were significantly lower than in the infected, whereas the r73 specific IgG1/IgG3 or IgG1/IgG2 in the PI and the infected individuals from Liberia or Ecuador, respectively, were similar. The IgG4 specific antibody response in the PI from Liberia and Ecuador were lower than in the infected. The T-cell proliferative responses to r73 in infected individuals from Cameroon were found to be inversely correlated with their levels of microfilariae.

Cloning of a cysteine protease required for the molting of Onchocerca volvulus third stage larvae

We have investigated the involvement of a cysteine protease in the development of Onchocerca volvulus fourth stage larvae (L4) by testing the effect of cysteine protease inhibitors on the survival of third stage larvae (L3), and the molting of L3 to L4 in vitro. When larvae were cultured in the presence of specific inhibitors, the peptidyl monofluoromethylketones, viability of either L3 or L4 was not affected. However, the inhibitors reduced the number of L3 that molted to L4 in vitro in a time- and dose-dependent manner. Molting was completely inhibited in the presence of 50-250 microM inhibitor. Ultrastructural examination of L3 that did not molt in the presence of inhibitors indicated that new L4 cuticle was synthesized, but there was no separation between the L3 and the L4 cuticles. The endogenous cysteine protease was detected in molting larvae after binding to labeled inhibitors, and by antibodies directed against a recombinant O. volvulus L3 cysteine protease that was cloned and expressed. The enzyme was detected in cuticle regions where the separation between the cuticles occurs in molting larvae. These studies suggest that molting and successful development of L4 depends on the expression and release of a cysteine protease.

Catenins and zonula occludens-1 form a complex during early stages in the assembly of tight junctions

We characterized the role of the E-cadherin adhesion system in the formation of epithelial tight junctions using the calcium switch model. In MDCK cells cultured in low (micromolar) calcium levels, the tight junctional protein Zonula Occludens-1 (ZO-1) is distributed intracellularly in granular clusters, the larger of which codistribute with E-cadherin. Two hours after activation of E-cadherin adhesion by transfer to normal (1.8 mM) calcium levels, ZO-1 dramatically redistributed to the cell surface, where it localized in regions rich in E-cadherin. Immunoprecipitation with ZO-1 antibodies of extracts from cells kept in low calcium and 2 h after shifting to 1.8 mM Ca2+ demonstrated the association of ZO-1 with alpha-, beta-, and gamma-catenins. E-cadherin was not detected in the ZO-1 immunoprecipitates but it was found in beta-catenin immunoprecipitates that excluded ZO-1, suggesting that the binding of ZO-1 to catenins may weaken the interaction of these proteins with E-cadherin. Immunofluorescence and immunoelectron microscopy confirmed a close association of beta-catenin and ZO-1 at 0 and 2 h after Ca2+ switch. 48 h after Ca2+ switch, upon complete polarization of the epithelium, most of the ZO-1 had segregated from lateral E-cadherin and formed a distinct, separate apical ring. The ZO-1-catenin complex was not detected in fully polarized monolayers. MDCK cells permanently transformed with Moloney sarcoma virus, which expresses low levels of E-cadherin, displayed clusters of cytoplasmic ZO-1 granules and very little of this protein at the cell surface. Upon transfection with E-cadherin into Moloney sarcoma virus-MDCK cells, ZO-1 redistributed to E-cadherin-rich lateral plasma membrane but later failed to segregate into mature tight junctions. Our experiments suggest that catenins participate in the mobilization of ZO-1 from the cytosol to the cell surface early in the development of tight junctions and that neoplastic transformation may block the formation of tight junctions, either by decreasing the levels of E-cadherin or by preventing a late event: the segregation of tight junction from the zonula adherens.

Transglutaminase-catalyzed reaction is important for molting of Onchocerca volvulus third-stage larvae

Highly insoluble proteins, which are probably cross-linked, are common in the cuticle and epicuticle of filarial parasites and other nematode species. We have investigated the possible involvement of transglutaminase (TGase)-catalyzed reactions in the development of Onchocerca volvulus fourth-stage larvae (L4) by testing the effects of TGase inhibitors on the survival of third-stage larvae (L3) and the molting of L3 to L4 in vitro. The larvae were cultured in the presence of three specific TGase inhibitors: monodansylcadaverine, cystamine, and N-benzyloxycarbonyl-D,L-beta-(3-bromo-4,5-dihydroisoxazol-5-yl)-al anine benzylamide. None of the inhibitors reduced the viability of either L3 or L4. However, the inhibitors reduced, in a time- and dose-dependent manner, the number of L3 that molted to L4 in vitro. Molting was completely inhibited in the presence of 100 to 200 microM inhibitors. Ultrastructural examination of L3 that did not molt in the presence of monodansylcadaverine or cystamine indicated that the new L4 cuticle was synthesized, but there was an incomplete separation between the L3 cuticle and the L4 epicuticle. The product of the TGase-catalyzed reaction was localized in molting L3 to cuticle regions where the separation between the old and new cuticles occurs and in the amphids of L3 by a monoclonal antibody that reacts specifically with the isopeptide epsilon-(gamma-glutamyl)lysine. These studies suggest that molting and successful development of L4 also depends on TGase-catalyzed reactions.

Identification and characterization of an Onchocerca volvulus cDNA clone encoding a highly immunogenic calponin-like protein

The identification and characterization of a recombinant cDNA clone, designated OV9M, expressing an antigen present in Onchocerca volvulus infective larvae and adult stages is described. Clone OV9M was identified by screening a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA using pooled rabbit antisera raised against the third (L3) and fourth (L4) stage larvae of the parasite. The cDNA clone encodes an open reading frame of 238 amino acids corresponding to a 27-kDa polypeptide. This polypeptide contains a series of five highly conserved repeats of 25 amino acids that are similar to repeats found in calponin, a protein previously only identified in vertebrate smooth muscle. Extension of the 5' end of the cDNA clone revealed two additional repeats extending the sequence to 378 amino acids, encoding a 41.8-kDa protein. Affinity purified antibodies, which bound specifically to the glutathione S-transferase-OV9M fusion polypeptide, recognize a series of antigens in extracts of O.volvulus microfilariae, L3, L4 and adult stages. The apparent molecular weight of the native OV9M protein in the adult is 45 kDa. Similar proteins are present in extracts of other nematodes including Caenorhabditis elegans, and antibodies from other filarial infections are cross reactive with glutathione S-transferase-OV9M fusion polypeptide. Immunoelectron microscopy revealed that the antigen encoded by this clone is present in the longitudinal muscles of the various larval stages and adult worms. Antibodies to the OV9M protein are present in 40-60% of both patently infected and non-patent individuals residing in onchocerciasis endemic areas.

Molecular cloning and characterization of onchocystatin, a cysteine proteinase inhibitor of Onchocerca volvulus

A cDNA clone designated OV7 encodes a polypeptide that corresponds to a highly antigenic Onchocerca volvulus protein. OV7 has significant amino acid sequence homology to the cystatin superfamily of cysteine proteinase inhibitors. In this report we establish that the OV7 recombinant protein is active as a cysteine proteinase inhibitor, and we have named it onchocystatin. It contains a cystatin-like domain that inhibits the activity of cysteine proteinases at physiological concentrations. Recombinant glutathione S-transferase-OV7 (GST-OV7, 1 microM) and maltose-binding protein-OV7 (MBP-OV7, 4 microM) fusion polypeptides inhibit 50% of the enzymatic activity of the bovine cysteine proteinase cathepsin B. Neither fusion polypeptide inhibits serine or metalloproteinases activity. The Ki for GST-OV7 fusion polypeptide is 170 nM for cathepsin B and 70 pM or 25 nM for cysteine proteinases purified from a protozoan parasite Entamoeba histolytica or the free living nematode Caenorhabditis elegans, respectively. The 5' end of the OV7 clone was isolated by polymerase chain reaction and sequenced, thus extending the previous cDNA clone to 736 base pairs. This represents the complete coding sequence of the mature onchocystatin (130 amino acids). A hydrophobic leader sequence of 32 amino acids was found, indicating a possible extracellular function of the onchocerca cysteine proteinase inhibitor.

Biosynthesis of lipoprotein: location of nascent apoAI and apoB in the rough endoplasmic reticulum of chicken hepatocytes

Our previous studies showed that in hepatic RER of young chickens, nascent apoAI is not associated with lipoprotein particles and only becomes part of these lipoprotein structures in the Golgi. In this study, we have used three different methodologies to determine the locations of apoAI and apoB in the RER and compared them to that of albumin. Immunoelectron microscopic examination of the RER cell fractions showed that both apoAI and apoB were associated only with the RER membrane whereas albumin was located both within the lumen and on the limiting membrane of the vesicles. To examine the possibility of membrane integration of nascent apoAI and apoB in the RER, we administered L-[3H]leucine to young chickens for 10 min, isolated RER, treated this cell fraction with buffers of varying pH, and measured the release of radioactive albumin, apoAI, and apoB. The majority of nascent apoAI (64%), nascent apoB (100%), and nascent albumin (97%) was released from RER vesicles at pH 11.2, suggesting that, like albumin, apolipoproteins are not integrated within the membrane. To determine if nascent apoproteins are exposed to the cytoplasmic surface, we administered L-[3H]leucine to young chickens and at various times isolated RER and Golgi cell fractions. Radioactive RER and Golgi cell fractions were treated with exogenous protease and the percent of nascent apoAI and apoB accessible to proteolysis was determined and compared to that of albumin. At 5, 10, and 20 min of labeling, 35-56% of nascent apoAI and 60-75% of apoB in RER were degraded, while albumin was refractive to this treatment. At all times both apolipoproteins and albumin present in Golgi cell fractions were protected from proteolysis. These biochemical and morphological findings indicate that apoAI and apoB are associated with the rough microsomal membrane and are partially exposed to the cytoplasmic surface at early stages of secretion. They may later enter the luminal side of the ER and, on entering the Golgi, form lipoprotein particles.

Immunity in hepatitis C infection

Polymerase chain reaction (PCR) and newer serologic assays for hepatitis C virus (HCV) were used to investigate 19 HCV cross-challenge episodes in chimpanzees. In these cross-challenges, 59% showed seroconversion after challenge, 33% showed reappearance of HCV-associated hepatocellular ultrastructural changes, 5 animals not PCR-positive at the time of challenge showed return of PCR positivity, and 26% developed hepatitis after rechallenge. A total of 74% showed at least one of these signs of reinfection. The frequency of development of serologic and ultrastructural responses was, however, reduced in secondary compared with primary infections (P less than .01). In 10 animals, the cross-challenge was done with heterologous strains, and in 9 with the originally infecting virus. There was no significant difference in the responses to homologous and heterologous challenges. The data suggest relatively weak immunity in HCV infections.

Identification and characterization of an Onchocerca volvulus cDNA clone encoding a microfilarial surface-associated antigen

The identification and characterization of a recombinant cDNA clone (OV103) expressing a microfilarial surface-associated antigen of Onchocerca volvulus is described. OV103 was identified and isolated from a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA using a chimpanzee antiserum, taken 2 years after infection with third-stage larvae of O. volvulus. The cDNA clone encodes a 12.5-kDa protein that corresponds to a 15-kDa parasite protein present in microfilariae and adult female worms. The antigen encoded by this clone is located in the basal layer of the cuticle and the hypodermis of the female adult worm, and on the surface of microfilariae. OV103 fusion polypeptide is recognized only by some sera from onchocerciasis infected subjects (57%), but more significantly (89%) by sera from individuals that have low levels of patent infection. In addition, the antibody response to this protein developed before appearance of microfilariae in the skin of chimpanzees that had developed non-patent or low level patent infections, while the antibody response in chimpanzees with high levels of microfilariae appeared later at the time of appearance of microfilariae. Preliminary experiments indicated that affinity purified antibodies directed against OV103 fusion polypeptide mediated killing of nodular microfilariae in vitro in the presence of normal peripheral blood granulocytes.

Diagnostic tests for choreoacanthocytosis

Two patients with striatal atrophy and a clinical syndrome consistent with choreoacanthocytosis had normal dried blood smears but their red cells demonstrated an abnormal sensitivity to various conditions known to promote discocyte-echinocyte transformation. Dilution in normal saline, in vitro aging, and contact with glass caused a great proportion of these patients' red cells to develop multiple spiny or rounded projections. Under identical conditions, such shape changes did not occur in normal patients or in those with Huntington's disease. Scanning electron microscopy showed that the age-induced increase in acanthocytic-appearing cells could be reversed with chlorpromazine. These data suggest that the red cells from these patients with striatal degeneration are deficient in their ability to preserve normal shape in the face of echinocytic stress and that this observation has diagnostic and, possibly, pathophysiologic significance.

Characterization of an Onchocerca volvulus cDNA clone encoding a genus specific antigen present in infective larvae and adult worms

The isolation and characterization of a recombinant cDNA clone (OV7) expressing an antigen present in Onchocerca volvulus infective larvae and adult stages is described. Using chimpanzee antiserum generated against irradiated infective larvae, we isolated a cDNA clone from a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA. The open reading frame encodes 131 amino acids corresponding to a 15.2-kDa protein. Affinity purified antibodies which bound specifically to OV7 fusion polypeptide recognized a single antigen with an apparent molecular weight of 17,000 in extracts of L3, L4 and adult worms. Immunoelectron microscopy established that the antigen encoded by this clone is present in the hypodermis and the basal layer of the cuticle of L3 and female adult worm, and in the egg shell around developing microfilariae. Since the OV7 fusion polypeptide is onchocerca-specific and is recognized specifically by sera from onchocerciasis patients, and sera from non-patent but infected chimpanzees, and not by sera from patients with other filarial parasites, it may have potential as an antigenic component in a test for detection of non-patent and patent infections of O. volvulus. The OV7 amino acid sequence contains residues that have a probable homology with the cysteine proteinase inhibitor superfamily.

Onchocerca volvulus: biochemical and morphological characteristics of the surface of third- and fourth-stage larvae

The annulated cuticles of third- and fourth-stage larvae of Onchocerca volvulus have the typical structure of other nematodes but the cuticle of fourth-stage larvae was thinner. The surface of the third-stage larva was wrinkled and fuzzy, while that of the fourth-stage was smooth. Intermediate stages in the formation of the new cuticle and epicuticle beneath the old basal layer and of the separation of the cuticles are shown. Monoclonal antibodies specific to the surface of third-stage larvae did not react with the surface of the fourth-stage larvae. Binding of the monoclonal antibodies to the third-stage larvae was abrogated by treatment of the worms with trypsin and proteinase K, but was unaffected by treatment with periodate or the detergents sodium deoxycholate and SDS. The lectins RCA120 and WGA, but not any of the other lectins tested, bound only to the surface of fourth-stage larvae, and not to that of third-stage larvae. The surfaces of third- and fourth-stage larvae were shown to be different and contained stage-specific surface epitopes.

Effect of phosphatidylserine on the shape of McLeod red cell acanthocytes

The rare McLeod blood group phenotype is characterized by weak Kell antigens, lack of the common Kx antigen, and acanthocytic morphology. Previous studies that did not detect membrane or cytoskeletal protein abnormalities suggested a lipid disturbance. In normal red cells, dimyristoyl phosphatidylserine (DMPS) is transported across the membrane by an enzymatic process and accumulates in the inner leaflet of the membrane bilayer causing discocyte to stomatocyte shape changes. Scanning electron microscopy of McLeod red cells shows a mixture comprised of 15% discocytes, 51% with irregular surfaces, and 34% acanthocytes. On incubation with various concentrations of DMPS at 37 degrees C for periods up to two hours, McLeod red cells transported DMPS across the membrane and caused irregularly shaped and acanthocytic McLeod red cells to attain normal discocyte shape and later to become stomatocytes. Chlorpromazine, which at 0 degrees C preferentially partitions into the inner monolayer of the membrane, had a similar effect on the shape of McLeod red cells. This suggests that in McLeod cells acanthocytosis is due to a lack of lipid in the inner leaflet of the membrane bilayer but that the imbalance is not caused by defective transport of phosphatidylserine across the membrane.

Inactivation of the Hutchinson strain of hepatitis non-A, non-B virus in intravenous immunoglobulin by beta-propiolactone

beta-propiolactone (beta-PL) treatment has been evaluated for its ability to inactivate 10(3.5) chimpanzee infectious doses (CID50) of the Hutchinson strain of hepatitis non-A, non-B virus (HNANBV). Two chimpanzees were inoculated with a beta-PL-treated immunoglobulin solution to which this dose of the titrated virus had been added prior to beta-PL treatment. beta-PL treatment was performed in accordance with the production procedure used for a licensed intravenous immunoglobulin preparation. Neither animal developed hepatitis. When subsequently challenged with the same spiked immunoglobulin solution that had not been beta-PL treated, both animals developed clear-cut hepatitis non-A, non-B. The results of this experiment demonstrate that beta-PL treatment is effective for the inactivation of hepatitis non-A, non-B virus in intravenous immunoglobulin.

Spumaviruses isolated from sources containing agents of non-A, non-B (NANB) hepatitis do not cause NANB hepatitis

Serum and liver tissue containing infective non-A, non-B hepatitis virus were shown to contain a retrovirus-like agent that replicated when inoculated into chimpanzee liver cell cultures in vitro. The virus appeared to assemble its core particles in association with tubular structures reminiscent of those characteristically seen in non-A, non-B hepatitis virus-infected chimpanzee liver in vivo, and produced syncytial cytopathic effects in a number of continuous and a primary mammalian liver cells. The agents were neutralized by acute and convalescent sera from human and chimpanzee cases of non-A, non-B hepatitis, as well as by antisera against simian spumavirus type 7, but not type 6. Aluminum chloride failed to abolish viral infectivity. There was no evidence of virus replication or hepatitis in chimpanzees inoculated with a seventh passage of one of the isolates. Thus the data suggest that the isolates are not causally related to non-A, non-B hepatitis, as was previously postulated.

Hepatitis B virus proteins eliciting protective immunity

The immune response to current hepatitis B vaccines appears to be qualitatively different from the response elicited during recovery from natural infection. Such disparate responses can probably be explained by the absence or under-representation of preS- and the nucleoprotein core-specific determinants in the vaccines. The incorporation of these determinants into future vaccines may improve their efficacy.

Biosynthesis of spectrin and its assembly into the cytoskeletal system of Friend erythroleukemia cells

Friend erythroleukemia cells, grown in the presence of dimethyl sulfoxide for 3 d, synthesize unequal amounts of the two chains (alpha and beta) of spectrin with approximately 15-30% more beta than alpha spectrin. When cells were ruptured by nitrogen cavitation, nascent alpha and beta spectrin were found to be associated with a membranous cell fraction and were not detected in the soluble cytoplasmic cell fraction. Nascent membrane-bound spectrin appeared not to be protected by membranes, since it was susceptible to trypsin degradation in the absence of detergent. On fractionation of cells with 1% Triton X-100, more (1.75-fold) nascent spectrin was found in the Triton-soluble fraction than in the Triton-insoluble fraction (cytoskeleton). In the Triton-soluble fraction, there was 55% more nascent beta spectrin than alpha spectrin, while the cytoskeleton contained nearly equal amounts of alpha and beta spectrin. Cells were pulse-labeled with L-[35S]methionine for 2 min and chase incubated for varying periods of time from 15 to 90 min with nonradioactive L-methionine. Radioactive spectrin accumulated in the Triton-soluble fraction for the first 15 min of chase incubation and then dropped by 25% in the next hour. By contrast, the amount of radioactive spectrin in the Triton-insoluble fraction rose gradually for 1 h of the chase period. This indicates that, in Friend erythroleukemia cells, a pool of membrane-bound spectrin containing an excess of the beta polypeptide is used to form the cytoskeletal system which is composed of equal molar amounts of alpha and beta spectrin. The location of spectrin was determined by immunoelectron microscopy. Small amounts of spectrin were detected in cells not treated with dimethyl sulfoxide and in these cells it was located on the surface membrane and within the cytoplasm. On treatment with dimethyl sulfoxide, complex vacuolar structures containing viruses appeared in the cells. In cells treated with dimethyl sulfoxide for 3 d 30% of the spectrin was near the outer membrane and 25% was associated with vacuolar structures, whereas in cells treated for 5 and 7 d the majority of spectrin (57-61%) was located in the vacuolar areas.

Inactivation of the Hutchinson strain of non-A, non-B hepatitis virus by combined use of beta-propiolactone and ultraviolet irradiation

A beta-propiolactone/ultraviolet irradiation procedure (beta PL/UV) has been evaluated for its ability to inactivate 30,000 chimpanzee infectious doses of the Hutchinson strain of non-A, non-B (NANB) virus. The chimpanzees were inoculated with plasma to which this dose of the titrated virus had been added prior to application of the beta PL/UV process in accordance with a procedure used for licensed blood derivatives in Germany. Neither animal developed hepatitis. When subsequently challenged with the same contaminated plasma, which had not been sterilized, both animals promptly developed typical NANB hepatitis. This study extends the high (approximately 10(7)-fold) process efficiency of the beta PL/UV procedure previously reported for hepatitis B virus to a blood-borne NANB virus.

Non-A, non-B hepatitis: is there more than a single blood-borne strain?

Fourteen chimpanzees were challenged with the Hutchinson strain inoculum that has been shown by many workers to produce non-A, non-B (NANB) hepatitis associated with characteristic cytoplasmic ultrastructural changes observable by electron microscopy. Nine of these animals had a history of definite NANB hepatitis induced by seven different human viral isolates; all of these animals resisted rechallenge. The five animals without a history of NANB hepatitis all developed definite histological changes associated with NANB hepatitis after challenge. Homologous rechallenge with a 100-fold higher infectivity titer was carried out in five of the nine chimpanzees. Cytoplasmic ultrastructural changes developed after challenge in two of these animals; the remaining three had evidence of possible mild reinfection on the basis of liver histopathology or mild elevations of transaminase or both. We conclude that most, if not all, blood-borne NANB isolates belong to a single class of agents and that this virus produces immunity to rechallenge, but this immunity may be overwhelmed by high-dose inocula.

Isolation of a virus from chimpanzee liver cell cultures inoculated with sera containing the agent of non-A, non-B hepatitis

A membrane-coated virus having a diameter of 85-90 nm and containing a 40-45 nm core was found to replicate in cell cultures derived from chimpanzee liver after inoculation of serum containing infective non-A, non-B (NANB) hepatitis viruses from two independent sources. Replication of this agent was not observed when the same cells were inoculated with a chloroform-extracted inoculum or were left uninoculated. Replication involves assembly of virus cores on tubular structures similar to those seen in liver cells of chimpanzees infected with most isolates of NANB virus.

Inactivation of hepatitis B and Hutchinson strain non-A, non-B hepatitis viruses by exposure to Tween 80 and ether

Titrated stocks of hepatitis B virus and Hutchinson strain non-A, non-B hepatitis virus were diluted in normal serum to contain, respectively, greater than or equal to 10(6) and greater than or equal to 10(4) chimpanzee infectious doses (CID50) per milliliter and exposed to 1% Tween 80 and 20% ether at 4 degrees C for 18 h. After evaporation of the ether, the treated sera were each inoculated into two chimpanzees. The animals remained free of serologic and biochemical evidence of hepatitis during a 6-month follow-up period, and were then shown to be susceptible to infection by challenge with the original untreated inocula. To assess the effect of exposure to Tween 80/ether on coagulation factors, four lots of antihemophilic factor (AHF) concentrate and 2 lots of commercial factor IX concentrate were treated as above. For the AHF concentrate there was an average of 70% recovery of factor VIII procoagulant activity, 93% recovery of factor VIII-related antigen, and 73% recovery of fibronectin opsonin activity and no detectable change in ristocetin cofactor activity or in fibronectin antigen. Crossed immunoelectrophoresis revealed no change in migration rate of fibrinogen, fibronectin, and von Willebrand factor (vWF), although the quantity of fibrinogen was reduced. Factor VIII procoagulant activity and vWF activity remained associated during chromatography on BioGel A15.

Blood-borne non-A, non-B hepatitis: lack of infectivity of feces from chimpanzees infected with a strain producing cytoplasmic tubular alterations

Fecal and serum samples from a chimpanzee with acute-phase, blood-borne non-A, non-B hepatitis were administered to four chimpanzees. Fecal material given either intravenously or orally did not result in abnormal levels of alanine aminotransferase or the occurrence of ultrastructural alterations in hepatocellular cytoplasm characteristic of non-A, non-B hepatitis during a one-year period of follow-up. Definite non-A, non-B hepatitis was later demonstrated in two of these animals four weeks after inoculation of acute-phase serum. Thus, feces do not appear to transmit this human strain of blood-borne non-A, non-B hepatitis.

Interference between non-A, non-B and hepatitis B virus infection in chimpanzees

Pre-existing chronic or concurrent acute non-A, non-B (NANB) virus infection has been found to interfere with hepatitis B virus (HBV) replication and to delay and moderate markedly the appearance of disease related to HBV infection in chimpanzees. The mechanism for this phenomenon remains unclear. These findings are of practical significance for vaccine safety testing and evaluation of methods for virus inactivation in chimpanzees. The possible occurrence of dual NANB and HBV infection requires that prolonged follow-up be carried out. Attempts to carry out inactivation studies on materials containing both types of virus may also provide misleading observations.

Isolated guinea pig adrenocortical cells in vitro: morphology and steroidogenesis in control and ACTH-treated cultures

Isolated guinea pig adrenocortical cells were maintained in long-term culture in order to perform sequential experiments on the same cell populations. The cells produced fluorogenic steroids, shown by thin-layer chromatography to be at least aldosterone, cortisol, and corticosterone. In addition, they increased production of these steroids when treated with either ACTH or dibutyryl cyclic AMP. Of particular interest was the fact that cultures treated for the initial 24-hour culture period with ACTH maintained enhanced levels of secretion for several days in absence of hormone and had an enhanced response to ACTH later in the culture period. Such enhancement of secretion was not seen following early treatment with dibutyryl cyclic AMP. The fine structure of the ACTH-treated cells was consistent with increased steroidogenesis. They possessed more smooth-surfaced endoplasmic reticulum, larger mitochondrial crystal surfaces, and larger Golgi complexes than the cells in untreated cultures.

A correlated thin-section and freeze-fracture analysis of guinea pig adrenocortical cells

Comparison of the fine structural features of guinea pig adrenocortical cells as seen in thin sections with those revealed by freeze-fracture confirms the structural appearance of steroid-secreting cells as interpreted from thin sections and reveals significant new features of the membranous organelles. Smooth-surfaced endoplasmic reticulum appears as a network of tubules, interwoven or in parallel, and as cisternae, fenestrated and non-fenestrated. These elements are tightly packed in the deeper cortical cells, excluding other organelles from their domain. Tubules and fenestrated cisternae possess randomly distributed intramembranous particles on their PF faces, while closely packed non-fenestrated cisternae possess aggregates of particles interspersed with aparticulate regions on their PF faces. These differences in particle distribution suggest functional specialization among the various forms of reticulum. Mitochondria appear as elongated structures of varying shape. Freeze-fracture reveals that all their cristae have circular origins from the inner membrane. Sinuous tubules, which appear as tubules in section, and straight tubules, which appear as lamellae in section, arise from single sites. Flattened sac-like cristae may have multiple circular origins. Definite contact points seen between inner and outer membranes may facilitate passage of molecules, including steroids, into the mitochondrial compartments. Lysosomes and peroxisomes, which are easily identified in thin sections with the aid of cytochemistry, are difficult to identify with certainty by freeze-fracture. Single membrane-bound granules of slightly smaller diameter than mitochondria may represent lysosomes. Smaller granules interconnected with the tubular reticulum, as well as dilated regions of this organelle, may represent peroxisomes. Plasma membranes show no indication of tight junctions but do have abundant gap junctions which show a zonal differentiation: small gap junctions throughout the cortex, medium-sized regularly shaped gap junctions in zona fasciculata externa, and large irregular gap junctions in zona fasciculata interna and zona reticularis. The large junctions cover planar areas as well as surfaces of projections of one cell into another. Such junctions may allow passage of ions as well as of low-molecular-weight substances between the cells, facilitating or even amplifying the response to trophic hormone stimulation.