Mechanisms of hypersensitivity: cellular interactions. Basophil arrival and function in tissue hypersensitivity reactions.

Bone marrow-derived blood basophils are recruited into the tissues by immuno mechanisms in a variety of delayed time-course hypersensitivity responses. In the skin these are called cutaneous basophil hypersensitivity (CBH) reactions. In guinea pigs, it is now established that the elicitation of CBH is dependent on T cell- and/or (antibody)-triggered mechanisms. Both are subject to modulation. T cell-mediated CBH seems to be suppressed in basophil-poor tuberculin-type reactions. B cells mediate CBH via antibody of IgG1 isotype through mechanisms that involve Fc receptors, which can be competitively blocked. After basophils arrive at a CBH reaction they can be triggered by antigen to immediately release mediators such as histamine. Thus, one consequence of the arrival and accumulation of basophils at delayed hypersensitivity reactions is to augment the anaphylactic potential of a given tissue site. In reactions to parasites, release of mediators by tissue basophils seems to aid in the expulsion of these multicellular organisms, In addition, histamine released by recruited basophils, or by locally resident mast cells, may modulate some delayed reactions through stimulation of histamine-2 receptors on cells such as T lymphocytes. In mice, mast cell release of serotonin and subsequent stimulation of the local vasculature seems to be required to allow diapedesis and tissue accumulation of various bone marrow-derived accessory leukocytes in delayed-type hypersensitivity responses. Thus, basophils and mast cells, and their release of mediators such as vasoactive amines, are involved in the onset, development, and function of various tissue hypersensitivity responses.     

用APAAP桥联酶标技术快速诊断合胞病毒

应用碱性磷酸酶抗碱性磷酸酶（ＡＰＡＡＰ）桥联酶标技术，对１１６例急性下呼吸道感染的患儿，进行合胞病毒抗原快速诊断研究，并与免疫荧光（ＩＦＡ）技术对照。二者阳性符合率９８．００％，阴性符合率９５．３８％，准确性为９６．５５％，进一步证明，ＡＰＡＡＰ桥联酶标技术特异性好，灵敏性高，用于呼吸道细胞检测，无内源性酶的干扰，并且操作简便，无需荧光显微镜，优于ＩＦＡ技术，可用于合胞病毒感染的快速诊断；与ＩＦＡ技术联用，可提高阳性检出率。     

Traditional and emerging methods for analyzing cell activity in cell culture

The selection of appropriate techniques to assay for markers of cell activity is important for obtaining optimal results in cell culture-based research. This paper is intended as a guide to many of the assays currently available and new techniques that have been recently introduced in the literature. This paper addresses both manual assay techniques, including the use of hemocytometers, phase contrast microscopy, cell staining, and the immunofluorescent antibody assay (IFA), and automated assays for cell activity, including stained optical density, proliferating cell nuclear antigen, creatine kinase assay, DNA quantification, electronic cell counting, flow cytometry, magnetic cell sorting, image analysis, chemiluminescence, radioisotope labeling, precursor incorporation, in-situ hybridization/ligand binding, and enzyme-linked immuno-culture assay (ELICA). Advantages/disadvantages and applicability of these assays to different areas of cell culture research are discussed, and guidelines for selecting an appropriate assay are suggested.     

Toll or Toll-Free Adjuvant Path Toward the Optimal Vaccine Development

Successful vaccines contain an adjuvant component that activates the innate immune system, thereby eliciting antigen-specific immune responses. Many adjuvants appear to be ligands for toll-like receptors (TLR), which are thus promising targets for the development of novel adjuvants to elicit vaccine immunogenicity. However, recent evidence suggests that some adjuvants activate the innate immune system in a TLR-independent manner possibly through other pattern recognition receptors and signaling machinery. In particular, newly identified intracellular retinoic-acid-inducible gene (RIG)-like receptors, NOD-like receptors, or even as yet unknown recognition machinery for the adjuvant may regulate TLR-independent vaccine immunogenicity. To develop optimal vaccines, it will be critical to understand how TLR-dependent and TLR-independent innate immune activation, by various adjuvants, control the consequent adaptive immune responses to vaccine.     

Q fever endocarditis in India: A report of two cases

Q fever is a zoonotic disease caused by the obligate intracellular bacterium Coxiella burnetii. Infective endocarditis is the most common form of chronic Q fever. Diagnosis of Q fever is difficult, as there are no pathognomonic symptoms. Methods of isolation of the organism in culture are tedious, hence serological and molecular techniques remain the mainstay of diagnosis. We report two cases of Q fever endocarditis diagnosed by IFA and real-time PCR.     

Correlations between synthetic peptide-based enzyme immunoassays and immunofluorescence assay for detection of human herpesvirus 8 antibodies in different Argentine populations

Human herpesvirus 8 (HHV-8) antibody tests vary in sensitivity and specificity, depending on the population tested and on the type of assay. In this study, we evaluated the sensitivity and specificity of two peptide enzyme immunoassays using a multiple antigenic peptide (PK8.1-MAP) or a chimeric peptide (PK8.1-orf65) as the antigens and determined the HHV-8 seroprevalence in different Argentine populations using an immunofluorescence assay (IFA) as reference. For analysis, when either or both of the peptide EIAs were positive, the specimen was considered positive (PEIA). We estimated the sensitivity and specificity of PEIA to be 97% using Kaposi's sarcoma (KS) patients and healthy individuals as positive and negative controls respectively. Then, we expanded the control groups to include IFA positive men who have sex with men (MSM) and IFA negative blood donors. The sensitivity decreased to 83% but specificity remained high at 98%. Concordance between PEIA and IFA was 77% for 1/40 IFA titers and increased to 90% for titers >or=1/160. Seroprevalences for HHV-8 performed in the HIV positive MSM were (IFA 73.1%; PEIA55.2%); heterosexuals (52.5%, 22.2%), which includes injecting drug users (IDU) (54.0%, 32.4%) and non-IDU (51.6%, 16.1%). The inclusion of non-KS HHV-8 IFA positive individuals to the positive controls may be a substantial improvement towards the realistic assessment of assay sensitivity. These peptide EIAs can be used for trends in populations with high probability of being HHV-8 infected and negative results should be confirmed by IFA. IFA test is still the most suitable test for populations with low probabilities of being infected.     

Clinical performance of different SARS-CoV-2 IgG antibody tests

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological assays are urgently needed for rapid diagnosis, contact tracing, and for epidemiological studies. So far, there is limited data on how commercially available tests perform with real patient samples, and if positive tested samples show neutralizing abilities. Focusing on IgG antibodies, we demonstrate the performance of two enzyme-linked immunosorbent assay (ELISA) assays (Euroimmun SARS-CoV-2 IgG and Vircell COVID-19 ELISA IgG) in comparison to one lateral flow assay (FaStep COVID-19 IgG/IgM Rapid Test Device) and two in-house developed assays (immunofluorescence assay [IFA] and plaque reduction neutralization test [PRNT]). We tested follow up serum/plasma samples of individuals polymerase chain reaction-diagnosed with COVID-19. Most of the SARS-CoV-2 samples were from individuals with moderate to the severe clinical course, who required an in-patient hospital stay. For all examined assays, the sensitivity ranged from 58.8 to 76.5% for the early phase of infection (days 5-9) and from 93.8% to 100% for the later period (days 10-18).     

Bartonella spp. bacteremia in high-risk immunocompetent patients

Serum and blood samples from 192 patients, who reported animal exposure (100.0%) and recent animal bites or scratches (88.0%), were screened for antibodies by indirect immunofluorescence assays and for bacteremia using the BAPGM (Bartonella alpha Proteobacteria growth medium) platform. Predominant symptoms included fatigue (79.2%), sleeplessness (64.1%), joint pain (64.1%), and muscle pain (63.0%). Bartonella spp. seroreactivity or bacteremia was documented in 49.5% (n = 95) and 23.9% (n = 46) of the patients, respectively; however, indirect immunofluorescence antibodies were not detected in 30.4% (n = 14) of bacteremic patients. Regarding components of the BAPGM platform, Bartonella DNA was amplified from 7.5% of blood (n = 21), 8.7% of serum (n = 25), and 10.3% of enrichment culture samples (n = 29). Polymerase chain reaction (PCR) on only extracted blood would not have detected Bartonella infection in 34.7% (16/46) of bacteremic patients. Serology, in conjunction with blood, serum, and BAPGM enrichment culture PCR, facilitates the diagnosis of Bartonella spp. bacteremia in immunocompetent patients.     

Anaplasma Phagocytophilum Intragranulocytic Morulae in Aborting Sheep: A Herd Case in Sicily

The present report describes the haematological and serological findings observed in a dairy sheep farm during an aborting outbreak. Fifty ewes divided into two groups were included in the study: group A consisted of 35 healthy ewes and group B consisted of 15 ill subjects. From each ewe, blood samples were collected for microscopic examination and serological assay. After 3 months, all ewes were subjected to microscopic examination, serological and biochemical assay. Morula‐containing granulocytes characteristic of A. phagocytophilum was observed in all animals of group B. Antibodies against A. phagocytophilum were observed in only one animal of group A. Seroconversion was observed after 3 months in five ewes of group A and all animals of group B. Only one subject with negative serology was positive to PCR. Our results confirm the endemicity of sheep tick‐borne fever (TBF) in Sicily and the problem to breeding in an endemic area. We suggest that is necessary to combine the different assays depending on the stage of infection for a correct diagnosis in endemic areas. Periodic evaluation of seroconversion could be helpful to evaluate the progression of TBF in a flock.