Antigen In Various Tissues Research Articles

Acute Rheumatic Fever (ARF) in a patient of Chronic Mucocutaneous Syndrome or Mucocutaneous Candidiasis having Diarrhea and Skin Rash

Acute Rheumatic fever (ARF) is the most common cause of acquired heart disease in the developing world. It is an immunological reaction to group A beta-hemolytic streptococcus Pyogenes. It occurs 2-4 weeks after group A streptococcal pharyngitis due to the development of antistreptococcal antibodies that cross-react with antigens in various tissues of the body, especially cardiac and basal ganglia neuronal antigens. Clinical features of acute rheumatic fever include fever, joint pain, myocarditis, nodules in subcutaneous tissue, Erythema Marginatum, and chorea. Patients with immunodeficiency like mucocutaneous candidiasis are especially prone to recurrent mucocutaneous infections (tonsillopharyngitis, thrush, skin abscess), which can predispose to acute rheumatic fever and subsequent development of rheumatic heart disease over the years. Keywords: Acute rheumatic fever, chronic mucocutaneous syndrome, skin rash,

Expression and immunofluorescent localization of the Edwardsiella tarda EvpC protein in infected Pelteobagrus fulvidraco

To determine the expression and localization of immunofluorescent secretory proteins encoded by Edwardsiella tarda (E. tarda) EvpC gene in tissues of experimentally infected yellow catfish Pelteobagrus fulvidraco (P. fulvidraco), an indirect immunofluorescent staining method was performed for detecting EvpC protein. A rabbit anti-EvpC polyclonal antibody, raised against a recombinant 6× His-EvpC fusion protein expressed in Escherichia coli, was prepared, purified, and used as the primary antibody. Sixty fish (50 ± 2.2 g) were intraperitoneally administered with E. tarda (infected group). Tissues were collected and prepared for indirect immunofluorescent staining at 4, 8, 12, 24, 48, 72, and 96 h post-inoculation. E. tarda EvpC encoding protein antigens could be detected in the liver, spleen, and kidney at 4 h after challenge, in the intestine at 12 h after challenge, in brain tissue 24 h after challenge, and in renal interstitium and liver tissue at 48 h. In addition, the intensity of positive staining of E. tarda EvpCp antigen in various tissues increased sharply from 8 to 96 h, peaking around 48–72 h, and subsequently decreasing steadily after 96 h, thus suggesting the expression levels of E. tarda EvpCp in systemic organs to be closely correlated with disease progression. The distribution pattern of E. tarda EvpCp was more prevalent in the spleen, liver, and kidney after infection, than in the intestine and gills. The present study may be useful not only for describing the characteristics of EvpCp expression and distribution in the chosen tissue of P. fulvidraco, but also for understanding pathogenesis by E. tarda and providing a basis for further functional analysis of the gene.

646. Activated Macrophages as Pathogenesis Factors in Ebola Virus Disease in Humans

BackgroundEbola virus disease (EVD) is associated with elevated cytokine levels that are more pronounced in fatal cases. This type of hyperinflammatory state is reminiscent of other inflammatory disorders, such as macrophage activation syndrome (MAS) or hemophagocytic lymphohistiocytosis (HLH). These are both part of a spectrum of rheumatologic phenomena characterized by both macrophage and T-cell activation. These disorders can be secondary to infection, malignancy, underlying rheumatologic disorder, or, paradoxically, immune deficiency.MethodsTwo cohorts of EVD patients were evaluated with respect to common plasma markers of HLH/MAS. Immunohistochemistry was used to evaluate tissue macrophages and viral antigens in various tissues from fatal cases of EVD.ResultsNeither fibrinogen nor soluble IL-2 receptor were significantly different between fatal and nonfatal cases. However, elevated levels of triglycerides, ferritin and sCD163, a marker of macrophage activation were noted in patients with EVD and they correlated with disease severity and a fatal outcome. Furthermore, significant immunoreactivity for CD163 + cells in host tissues was observed in fatal cases, predominantly in areas of extensive immunostaining for EBOV antigens.ConclusionThese data suggest that host macrophage activation contributes to EVD pathogenesis and that directed anti-inflammatory therapies could be beneficial in the treatment of EVD.Disclosures All authors: No reported disclosures.

Autoimmune-associated Congenital Heart Block: A New Insight in Fetal Life.

Objective:Congenital heart block (CHB) is a rare but life-threatening disorder. More than half of CHB cases are associated with maternal autoimmune, which are termed as autoimmune-associated CHB. This review summarized the recent research findings in understanding autoimmune-associated CHB, discussed the current diagnostic approaches and management strategies, and summarized the problems and future directions for this disorder.Data Sources:We retrieved the articles published in English from the PubMed database up to January 2017, using the keywords including “Autoimmune-associated”, “Autoimmune-mediated”, and “Congenital heart block”.Study Selection:Articles about autoimmune-associated CHB were obtained and reviewed.Results:Observational studies consistently reported that transplacental maternal antibodies might recognize fetal or neonatal antigens in various tissues and result in immunological damages, but the molecular mechanisms underlying CHB pathogenesis still need illuminated. Multiple factors were involved in the process of atrioventricular block development and progression. While several susceptibility genes had been successfully defined, how these genes and their protein interact and impact each other remains to be explored. With currently available diagnostic tools, fetal ultrasound cardiography, and fetal magnetocardiography, most of CHB could be successfully diagnosed and comprehensively evaluated prenatally. The efficacy of current approaches for preventing the progression and recurrence of CHB and other autoimmune-mediated damages was still controversial.Conclusions:This review highlighted the relationships between autoimmune injuries and CHB and strengthened the importance of perinatal management and therapy for autoimmune-associated CHB.

Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures

Immunoelectron microscopy is a powerful tool to study biological molecules at the subcellular level. Antibodies coupled to electron-dense markers such as colloidal gold can reveal the localization and distribution of specific antigens in various tissues. The two most widely used techniques are pre-embedding and post-embedding techniques. In pre-embedding immunogold-electron microscopy (EM) techniques, the tissue must be permeabilized to allow antibody penetration before it is embedded. These techniques are ideal for preserving structures but poor penetration of the antibody (often only the first few micrometers) is a considerable drawback. The post-embedding labeling methods can avoid this problem because labeling takes place on sections of fixed tissues where antigens are more easily accessible. Over the years, a number of modifications have improved the post-embedding methods to enhance immunoreactivity and to preserve ultrastructure. Tissue fixation is a crucial part of EM studies. Fixatives chemically crosslink the macromolecules to lock the tissue structures in place. The choice of fixative affects not only structural preservation but also antigenicity and contrast. Osmium tetroxide (OsO4), formaldehyde, and glutaraldehyde have been the standard fixatives for decades, including for central nervous system (CNS) tissues that are especially prone to structural damage during chemical and physical processing. Unfortunately, OsO4 is highly reactive and has been shown to mask antigens, resulting in poor and insufficient labeling. Alternative approaches to avoid chemical fixation include freezing the tissues. But these techniques are difficult to perform and require expensive instrumentation. To address some of these problems and to improve CNS tissue labeling, Phend et al. replaced OsO4 with uranyl acetate (UA) and tannic acid (TA), and successfully introduced additional modifications to improve the sensitivity of antigen detection and structural preservation in brain and spinal cord tissues. We have adopted this osmium-free post-embedding method to rat brain tissue and optimized the immunogold labeling technique to detect and study synaptic proteins. We present here a method to determine the ultrastructural localization of synaptic proteins in rat hippocampal CA1 pyramidal neurons. We use organotypic hippocampal cultured slices. These slices maintain the trisynaptic circuitry of the hippocampus, and thus are especially useful for studying synaptic plasticity, a mechanism widely thought to underlie learning and memory. Organotypic hippocampal slices from postnatal day 5 and 6 mouse/rat pups can be prepared as described previously), and are especially useful to acutely knockdown or overexpress exogenous proteins. We have previously used this protocol to characterize neurogranin (Ng), a neuron-specific protein with a critical role in regulating synaptic function . We have also used it to characterize the ultrastructural localization of calmodulin (CaM) and Ca(2+)/CaM-dependent protein kinase II (CaMKII). As illustrated in the results, this protocol allows good ultrastructural preservation of dendritic spines and efficient labeling of Ng to help characterize its distribution in the spine. Furthermore, the procedure described here can have wide applicability in studying many other proteins involved in neuronal functions.

Inactivation of infectious virus and serological detection of virus antigen in Rift Valley fever virus-exposed mosquitoes fixed with paraformaldehyde

Formaldehyde is routinely used to fix tissues in preparation for pathology studies, however concerns remain that treatment of tissues with cellular fixatives may not entirely inactivate infectious virus particles. This concern is of particular regulatory importance for research involving viruses that are classified as select agents such as Rift Valley fever virus (RVFV). Therefore, the specific aims of this study were to (1) assay RVFV-exposed Aedes aegypti mosquitoes fixed in 4% paraformaldehyde for the presence of infectious RVFV particles at various time points following infection and (2) demonstrate the utility of immunofluorescence assay (IFA) for the detection of RVFV antigen in various tissues of paraformaldehyde-fixed mosquitoes. Mosquitoes were administered an infectious blood meal containing one of two strains of RVFV, harvested at various time points following infection, intrathoracically inoculated with 4% paraformaldehyde, and fixed overnight at 4°C. The infection status of a subset of mosquitoes was verified by IFA on leg tissues prior to fixation, and infectivity of RVFV in fixed mosquito carcasses was determined by Vero cell plaque assay. Paraformaldehyde-fixed mosquitoes harvested 14 days post infection were also paraffin-embedded and sectioned for detection of RVFV antigen to particular tissues by IFA. None of the RVFV-exposed mosquitoes tested by Vero cell plaque assay contained infectious RVFV after fixation. Furthermore, incubation of mosquito sections with trypsin prior to antibody staining is recommended for optimal visualization of RVFV antigen in infected mosquito tissues by IFA.

Expression and Distribution of the Duck Enteritis Virus UL51 Protein in Experimentally Infected Ducks

To determine the expression and distribution of tegument proteins encoded by duck enteritis virus (DEV) UL51 gene in tissues of experimentally infected ducks, for the first time, an immunoperoxidase staining method to detect UL51 protein (UL51p) in paraffin-embedded tissues is reported. A rabbit anti-UL51 polyclonal serum, raised against a recombinant 6-His-UL51 fusion protein expressed in Escherichia coli, was prepared, purified, and used as primary antibodies. Fifty-eight 30-day-old DEV-free ducks were intramuscularly inoculated with the pathogenic DEV CHv strain as infection group, and two ducks were selected as preinfection group. The tissues were collected at sequential time points between 2 and 480 hr postinoculation (PI) and prepared for immunoperoxidase staining. DEV UL51p was first found in the spleen and liver at 8 hr PI; in the bursa of Fabricius and thymus at 12 hr PI; in the Harders glands, esophagus, small intestine (including the duodenum, jejunum, and ileum), and large intestine (including the caecum and rectum) at 24 hr PI; in the glandularis ventriculus at 48 hr PI; and in the pancreas, cerebrum, kidney, lung, and myocardium at 72 hr PI. Throughout the infection process, the UL51p was not seen in the muscle. Furthermore, the intensity of positive staining of DEV UL51p antigen in various tissues increased sharply from 8 to 96 hr PI, peaked during 120-144 hr PI, and then decreased steadily from 216 to 480 hr PI, suggesting that the expressional levels of DEV UL51p in systemic organs have a close correlation with the progression of duck virus enteritis (DVE) disease. A number of DEV UL51p was distributed in the bursa of Fabricius, thymus, spleen, liver, esophagus, small intestine, and large intestine of DEV-infected ducks, whereas less DEV UL51p was distributed in the Harders glands, glandularis ventriculus, cerebrum, kidney, lung, pancreas, and myocardium of DEV-infected ducks. Moreover, DEV UL51p can be expressed in the cytoplasm of various types of cells, especially most abundantly in the cytoplasm of lymphocytes, reticulum cells, macrophages, epithelial cells, and hepatocytes. The present study may be useful not only for describing the characteristics of UL51p expression and distribution in vivo but also for a greater understanding of the pathogenesis of this DVE.

Utilization of protein-A in immuno-histochemical techniques for detection of Peste des Petits Ruminants (PPR) virus antigens in tissues of experimentally infected goats

This paper constitutes the first record of utilizing the S. aureus protein-A (PA), conjugated to peroxidase enzyme, for the detection of the Peste des Petits Ruminants (PPR) virus antigens in tissues of experimentally infected goats. The goats were experimentally infected with a virulent PPR virus, which was previously isolated from a severe natural disease outbreak in gazelles, during 2002 in Saudi Arabia. The technique is rapid, and has the superiority over the peroxidase -anti-peroxidase (PAP) test in that, inactivation of the indigenous peroxidase in the tissues is not required and that it can be used against a wide range of animal species. An advantage over the other immunolabelled conjugates is that PA attaches specifically to the crystalizable fraction (Fc) of the IgG molecule, thus allowing the antigen binding fraction (Fab) of the molecule, free to interact specifically with the antigen. So, it doesn't actually compete with the antigen for the Fab portion of the IgG molecule. In the present study, PA conjugate detected the PPR virus antigens in various tissues of the experimentally infected goats.

Distribution of 28.5 kDa antigen in the tegument of adult Fasciola gigantica

Monoclonal antibody (MoAb) specific to 28.5 kDa tegumental antigen (TA) was used to localize this antigen in various tissues of adult Fasciola gigantica by means of indirect immunofluorescence, immunoperoxidase and immunogold techniques. The indirect immunofluorescence and immunoperoxidase detections revealed that this antigen was concentrated in the tegument particularly in its outer rim, tegumental cells and their processes, epithelial linings of the oral sucker and the proximal part of digestive tract. It was also detected at a moderate concentration in spermatogenic cells in the testes, cells of Mehlis’ gland, oocytes within the ovary, and ovum within the egg of adult parasites. At TEM level, the immunogold detection showed deposit of gold particles specifically in G 2 tegumental granules and on the surface membrane. Thus, this antigen is expressed in the tegument and associated structures of adult parasites, and it could be a major component of the G 2 granules which are shown to fuse with the surface membrane and contribute material to replace the casted-off membrane. This process is a part of membrane turnover that prevents the parasite from being attacked by the host immune effector cells.

Detection and Characterization of Naturally Acquired West Nile Virus Infection in a Female Wild Turkey

An adult female wild turkey exhibiting disorientation and failure to flee when approached was submitted to the Mississippi Veterinary Research and Diagnostic Laboratory. Gross pathologic examination revealed evidence of dehydration and the presence of modest numbers of adult nematodes in the small intestine. Histologic examination revealed extensive multifocal perivascular lymphocytic infiltration in brain, marked heterophilic hyperplasia in bone marrow, and multifocal interstitial lymphocytic infiltration in heart, pancreas, ventriculus, and skeletal muscles. West Nile virus (WNV) was isolated from the brain, lung, and kidney tissues using cultured Vero cells. Higher copies of viral RNA were detected from brain, lung, and kidney than from heart, liver, or spleen by quantitative real-time reverse transcription-polymerase chain reaction (RRT-PCR) analysis. Immunohistochemical (IHC) analysis detected WNV antigen in various tissues including neurons, kidney, respiratory tract epithelium, heart, and bone marrow. On the basis of the data from this investigation, it is concluded that WNV caused encephalitis along with many other pathologic changes in the affected wild turkey.

Identification of a key protein associated with cerebral ischemia

The biochemical effects of permanent focal ischemia following unilateral occlusion of the middle cerebral artery in rats were studied by determining the content of specific proteins of the affected areas in the cerebral hemisphere. Brain proteins were prepared 72 h after the occlusion and analyzed by sodium dodecylsulfate–polyacrylamide gel electrophoresis. A significant increase in 66 and 80 kDa components and a paradoxical decrease in 260 kDa protein occurred in the ischemic brain tissues. The 66 and 80 kDa protein bands were identified as albumin and transferrin, respectively. The 260 kDa protein was analyzed by peptide mass fingerprinting (PMF) and matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The isoelectric point of the 260 kDa protein was 4.65 determined by isoelectric focusing. The data obtained from PMF were used in searching the protein database for homologous components. Three proteins with partial homology were identified. They were the microtubule-associated protein 1A, protein-tyrosine phosphatase zeta precursor (phosphacan), and protein kinase A anchoring protein 6. Polyclonal antibodies against the 260 kDa protein were raised and used to immunolocalize the antigen in various tissues. Positive staining occurred with brain neurons and pyramidal cells, islet cells, podocytes of kidney glomeruli, and endothelial cells of the venous sinuses of the spleen. The localization of 260 kDa protein strongly implies its function in these tissues. Its physiological and pathophysiological significances need to be clarified in future.

MONOCLONAL-ANTIBODIES 5G8 AND 2H6 ARE COMPLEMENTARY IMMUNOHISTOCHEMICAL MARKERS OF LUNG CARCINOMAS

Two murine monoclonal antibodies (MAbs) 5G8 and 2H6 were generated by fusing spleen cells obtained from mice immunized with human fetal tissue extract (14 weeks, Nonidet P-40 membrane fraction) from the early first trimester, followed by a booster injection of a lung cancer cell line. The MAb 5G8 recognized antigens with a molecular weight of 90, 50, 20 kDa, was neuraminidase-resistant and showed cross-reactivity with both carcinoembryonic antigen and non-specific cross-reacting antigen. The MAb 2H6 reacted with a sialomucin whose molecular weight was more than 1000 kDa and was different from previously known tumor associated-marker antigens. The distribution of the MAb-recognizing antigens in various tissues was investigated immunohistochemically. In malignant epithelial tumors of the lung, acinar adenocarcinoma and bronchioloalveolar carcinoma were positive for both MAbs; papillary adenocarcinoma, squamous cell carcinoma, and adenoid cystic carcinoma were positive only for MAb 5G8; solid carcinoma with mucin formation, small cell carcinoma, and large cell carcinoma were positive only for MAb 2H6. The combination of the two MAbs covered almost all histological types of lung carcinomas (23 of 24 cases) except carcinoid tumors. MAbs 5G8 and 2H6 reacted also with a restricted number of adenocarcinomas of the other organs. MAb 5G8 did not react with normal fetal or adult tissues, except for metaplastic gastric mucosa, acinar cells of the breast and leucocytes, whereas MAb 2H6 reacted with the surface epithelium of the stomach and colon, the Brunner gland of the duodenum and uterine cervix as well as the epithelium of the fetal digestive tract. Thus, MAb 2H6 which recognized oncofetal sialomucin, played a complementary role to MAb 5G8 as a CEA-related MAb in the immunohistochemical diagnosis of lung carcinomas.

Prostatic specific antigen and immunoglobulin binding factor in human seminal plasma and prostate.

Antibodies raised against prostatic specific antigen (PSA) and immunoglobulin binding factor (IgBF) of human seminal plasma (SP) were used to localize the antigens in various tissues by Western blot. Both antigens were found only in the prostate, including benign prostatic hypertrophy and prostatic adenocarcinoma. The polyclonal anti-PSA antibodies stained five prostatic protein bands with estimated M(r) values of 10, 14, 22, 25, and 33 kD, whereas anti-IgBF antibodies stained a single 16-kD protein. No cross-reaction occurred between the two antibodies. When anti-PSA antibodies were used an additional protein with an estimated M(r) of 35 kD was detected in the extract of benign prostatic hypertrophy, but not with normal prostate or prostatic cancer. When SP and prostatic proteins were analyzed by SDS-PAGE under nonreducing condition and immunoblot with both antibodies, immunoreactive proteins with estimated M(r) of 125 and 140 kD, respectively, were stained, suggesting that both factors may be produced as an aggregated precursor molecule. Since IgBF was found only in the prostate, this component may be useful as a marker of prostatic tissue.

Development of an immunocytochemical procedure to detect adenoviral antigens in chicken tissues.

An immunocytochemical technique utilizing an avidin-biotin peroxidase complex was developed to detect viral antigens in various tissues following oral administration of a locally isolated serotype 8 avian adenovirus (AAV) in specific pathogen-free (SPF) chickens. A strong color reaction was obtained with tissues from infected birds that contained a minimal amount of AAV antigens as determined by an indirect enzyme-linked immunosorbent assay. No reaction was detected in sections of tissues obtained from SPF chickens, and the reactivity with infected tissues could be removed by prior absorption of the primary antibody with purified AAV. A group-specific antigen common to the 12 serotypes of AAV was demonstrated by this technique. Because of the high sensitivity and broad-spectrum reactivity, this technique could be useful for studying the pathogenesis and laboratory diagnosis of inclusion body hepatitis caused by several serotypes of AAV.

Quantitative Distribution of Cluster 1 Small Cell Lung Cancer Antigen in Cancerous and Non‐cancerous Tissues, Cultured Cells and Sera

Three monoclonal antibodies (mAbs), NCC‐LU‐243, ‐244 and ‐246, detected three different epitopes on a 145‐kDa cell membrane antigen, which had been designated as the cluster 1 antigen at the First International Workshop on Small Cell Lung Cancer (SCLC) Antigens. The distribution of the antigen in various tissues, cultured cells and sera was examined by immunohistochemistry and sandwich radioimmunoassay using these mAbs. The antigen is a normal differentiation antigen and is present in nenronal, nenroendocrine and cardiac muscle cells. The level of the antigen was highest in central nervous tissues, while it was undetectable in the liver, kidney and peripheral lung. Among tumor tissues, the antigen was detected only in SCLC, carcinoid tumor and neuroblastoma, indicating its usefulness as a marker for discriminating SCLC from non‐SCLC. The level of the antigen varied among SCLC tissues and tended to be lower in variant‐type cultured SCLC cells. Although an increase in the antigen level was observed in sera of some patients with advanced SCLC, the antigen did not possess any additional value over neuron‐specific enolase as a serum tumor marker for monitoring SCLC patients.

Development and distribution of rinderpest virus antigen in experimentally infected goats.

Three goats, experimentally infected with rinderpest virus were examined for the development and distribution of precipitating antigens in various tissues and secretions using the agar gel immunodiffusion test. Virus antigens were detected in ocular secretions and lymph node biopsies from the second to the fourth and fifth days of pyrexia, respectively, but were not detected in nasal secretions. Precipitating antigens were demonstrated in various lymphoid organs, the lung and abomasum of a goat killed on the fourth day of pyrexia. These findings are discussed in relation to the epidemiology of rinderpest in goats in Africa.

Spread of herpes simplex virus within ocular nerves of the mouse: demonstration of viral antigen in whole mounts of eye tissue.

Spread of herpes simplex virus to and within the mouse eye after inoculation of the cornea or the skin of the snout was examined by peroxidase-antiperoxidase (PAP) staining of viral antigen in flat mounts of the eye and by isolation of virus from nervous tissue. Following inoculation of virus at either site, viral antigen was found in ocular nerves. One to three days later antigen was also found in the iris, ciliary body and choroid/sclera suggesting that virus spread to these tissues occurred via their nerve supply. Viral antigen was also found in the retina of the uninoculated eye after corneal inoculation. After inoculation of the snout, virus was isolated from ophthalmic and maxillary parts of the trigeminal ganglion and the superior cervical ganglion and then from the brainstem, eye and mandibular part of the trigeminal ganglion. This sequence also suggested that virus reached the eye via the nerves and that this may occur indirectly via the brainstem. The PAP method allows rapid determination of the distribution of antigen in various tissues. Our observations suggest that widespread involvement of ocular tissue may occur by spread of virus in nerves within the eye.

Immunolocalization of a sperm membrane protein in human male reproductive organs

A monoclonal antibody that induces agglutination of human sperm was used to localize the interacting antigen in various tissues by indirect immunofluorescence. The antibody localized to the immature sperm and Sertoli cells of the seminiferous tubules, simple cuboidal epithelial cells of the rete testis, and the columnar epithelial cells of the ductuli efferentes. The present results show that the interacting protein is found associated with germ cells undergoing spermatogenesis.

Antibodies to paired helical filaments in Alzheimer's disease do not recognize normal brain proteins.

During ageing of the human brain, and particularly in senile dementia of the Alzheimer type (AD), many neurones progressively accumulate abnormal cytoplasmic fibres, called paired helical filaments (PHF). Each such fibre consists of a pair of intermediate (10 nm) filaments twisted into a double helix with a periodicity of 160 nm. PHF accumulate in large perikaryal masses, called neurofibrillary tangles, and are also found in degenerating cortical neurites that form neurite plaques. The density of PHF-containing neurites and cell bodies correlates with the degree of dementia and the extent of loss of cholinergic neurotransmitter function in AD. Recently, we demonstrated that PHF from human cerebral cortex are large, rigid polymers with unusual molecular properties, including insolubility in SDS, urea and other denaturing solvents and apparent resistance to protease digestion. These properties have so far prevented complete purification and analysis of the constituents of PHF. Based on their insolubility, we have developed a new method of preparing highly enriched PHF fractions and have raised an antiserum that is highly specific for PHF. We report here that this antiserum specifically labels PHF, free of any associated normal fibrous proteins and, unexpectedly, it reacts with neither neurofilaments nor any other normal cytoskeletal protein in brain sections or on immunoblotted gels. These anti-PHF antibodies have been used for the specific detection of Alzheimer-type PHF and in the search for cross-reacting antigens in various tissues, and are suitable for immunoaffinity purification of PHF. Our results indicate that PHF contain determinants that are not shared with normal neuronal fibrous proteins.

Immunofluorescence Studies on the Early Pathogenesis of Hemorrhagic Enteritis Virus Infection in Turkeys and Chickens

Chickens and turkeys not previously exposed to hemorrhagic enteritis virus (HEV) were inoculated orally with the virus. Birds were necropsied each day from the first to the eighth day following inoculation, and specimens from various tissues were collected for examination. Clinical illness was noted only in turkeys, although intestinal hemorrhages and swollen, necrotic spleens were seen in both species. The distribution and localization of viral antigens in various tissues and peripheral blood lymphocytes were studied by the immunofluorescent technique. The patterns of HEV infection in chickens and turkeys were similar, except there was a high level and persistence of viral antigen in the thymus of turkeys but not in chickens.