antigens

The human immune system consists of innate and adaptive immune responses which both provide protective immunity to microbial infection. The adaptive immune system consists of T and B cell which act as second line defense through production of neutralizing antibody by B cells and cytotoxic activity of CD8+ T cells. The CD4+ T-cell performs a central role in the immune responses. These cells also known as T4 or helper/inducer T lymphocytes recognize antigens presented by antigen presenting cells (APC) such as macrophages and monocytes. Once antigens such as bacteria and viruses are presented, CD4+ T lymphocytes orchestrate the body’s antigen-specific immune response by Coordinating B-lymphocyte production of antibodies to these antigens, producing cytokines and induction of cytotoxic T-lymphocytes. The paper was aimed to review the role of T-helper cells (CD4+ T cells) in human immune system against some microbial infections.

Typhoid fever is a systemic infection caused by Salmonella enterica serotype typhi. It is of major concern in tropical regions of the world. Highest episodes of typhoid fever occur in Asia i.e.93%. Early diagnosis of the disease is mandatory to lower the mortality rate associated with it as well as to prevent the emergence of antimicrobial drug resistance by Salmonella typhi. Research work was conducted in Immunology Department of the Children’s Hospital, Lahore for the period of one year including a total of 60 patients suspected of having typhoid fever. Serum samples of these patients were tested for typhidot IgG and IgM antibodies as well as for the antibodies against TO and TH antigens using Widal test. Of the total 60 patients, 10 (16.7%) were positive for both typhidot IgG and IgM, 16 (26.7%) were positive for typhidot IgM, 3 (5%) were Positive for typhidot IgG and 31 (51.66%) were negative for both typhidot IgG and IgM. Reading the results of Widal test, 8 (13.33%) were positive for Widal TO and TH antigens, 3 (5%) were positive for Widal TO antigen, 19 (31.7%) were positive for Widal TH antigen and 30 (50%) were negative for Widal TO and TH antigens. IgM is positive at the early stage of acute typhoid fever, IgM along with IgG positive means the middle stage of acute illness. The detection of only IgG cannot discriminate between acute and convalescent phases as it can stay in the serum for at least 2 years or more. The typhidot test is much helpful for the rapid diagnosis of typhoid fever as compared to Widal test which is still being used in some set ups in poor countries, although has become mostly obsolete. By testing the rise of IgM and IgG antibodies against Salmonella typhi, we can detect the infection at early and late stages, respectively

Red blood cell (RBC) alloimmunization can be a life-threatening complication for patients with thalassemia major and sickle cell disease (SCD) who must receive chronic therapeutic transfusions. Chronic transfusions can lead to erythrocyte alloimmunization, patients continue to develop alloantibodies due to the transference of the immunogenic antigens on the donor RBCs. Many complications are possible. Difficulty in finding compatible match units for the patients can cause transfusion delays delayed, or present alternative risks to the patients from delayed hemolytic transfusion reactions. This review discusses the possible mechanisms, risk factors associated with alloimmunization formation and the hemolytic transfusion reactions and also describe the guideline for transfusion management of these patients, including opportunities and emerging approaches for minimizing this life-threatening complication.

Background: Like other viruses, the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) appears to be responsible for several autoimmune complications. The occurrence of autoimmune hemolytic anemia has been described in several case reports. This AIHA was also noticeable by the important number of blood transfusions required for COVID-19 (coronavirus disease 2019) patients. By investigating RBC coating autoantibodies, this article attempts to clarify the autoimmune aspect of the anemia in the context of SARS-CoV-2 infection. Results: A large population of COVID-19 patients selected at Saint-Luc University Hospital showed an average of 44% DAT positivity. In this population, the intensive care patients were more prone to DAT positivity than the general ward patients (statistically significant result). The positive DAT appeared « transmissible » to other RBCs via COVID-19 DAT-positive patient’s plasma. Conclusion: The strongest hypothesis explaining this observation is the targeting of cryptic antigens by autoantibodies in COVID-19 patients.

Related the extremely transmittable abilities of SARS-CoV-2,a harmonious virus to the bat CoV, gets transmitted by three principal processes-- the inhalation of droplets from the SARS-CoV-2 infected person, contacting to the person, and by the surfaces and materials defiled with the virus. Whereupon bat Coronavirus is mostly like the pandemic causing virus SARS-CoV-2, bats are often deliberated and figured out as a possible primary host although no intermediate has not been defined yet in the wherewithal of transmission. The Spike Glycoprotein plays an important role in the case of penetration with the assistance of the ACE2 receptor and the Receptor Binding Domain. In the human body, infiltrating the nucleic acid into host cells, SARS-CoV-2 attacks one cell and one by one into the whole human body; therefore, infected cases are found symptomatic and asymptomatic considering the immune power. Patients with cardiovascular disease or diabetes proceed with their treatment with ACE2 often; therefore, there might be a high chance of getting infected. Whereas the SARS-CoV-2 infects the blood and then lungs, Antigens improvement can be better in order to avoid high-complicated effects. Currently, no vaccination or no accurate cure and treatment has not been defined. An explanation with analysis on SARS-CoV-2 has been performed from the aspect of virology, immunology and molecular biology. Several relevant figures have been included hereby in order to a better understanding of the very concept.

Flow cytometry (FCM) is a unique technique that allows rapid quantitative measurement of multiple parameters on a large number of cells at the individual level. FCM is based on immunolabelling with fluorochrome-conjugated antibodies, leading to high sensitivity and precision while time effective sample preparation. FCM can be performed on tissue following enzymatic or mechanical dissociation. The expression of epithelial antigens and cytokeratin isoforms help in distinguishing tumor cells from adjacent epithelial cells and from tumor infiltrating leukocytes. Tumor phenotypes can be characterized on expression intensity, aberrancies and presence of tumor-associated antigens as well as their cell proliferation rate and eventual heteroploidy. FCM can measure quantitative expression of hormone or growth factor receptors, immunoregulatory proteins to guide adjuvant therapy. Expression of adhesion molecules tells on tumor’s capacity for tissue invasion and metastasis seeding. Tumor heterogeneity can be explored quantitatively and rare, potentially emerging, clones with poor prognosis can be detected. FCM is easily applicable on fine needle aspiration and in any tumor related biological fluids. FCM can also be used to detect circulating tumor cells (CTC) to assess metastatic potential at diagnosis or during treatment. Detecting CTC could allow early detection of tumors before they are clinically expressed although some difficulties still need to be solved. It thus appears that FCM should be in the pathologist tool box to improve cancer diagnosis, classification and prognosis evaluation as well as in orientating personalized adjuvant therapy and immunotherapy. More developments are still required to better known tumor phenotypes and their potential invasiveness

Determining the extent of immunity induced by booster doses of COVID-19 vaccinations is crucial for informing recommendations for booster dose regimens as well as constant adjustments of immunization strategies amongst different groups of people within the population. The study involved 31 healthy volunteers (majority were healthcare professionals) who completed either vaccination course with Pfizer or Moderna mRNA vaccines and received a third dose of the vaccine. Here we report results on the evaluation of an antibody response to four different SARS-CoV-2 antigens: RBD, S1, S2 and nucleocapsid prior to third dose and two and four weeks after a booster vaccination. We detected a peak of high titers of antibodies after the third dose with a gradual decline after four weeks. No significant differences were seen between the two vaccines in terms of antibody response. There were no gender discrepancies between the two vaccines. Our results suggest that: third doses are necessary due to the emergence of different SARS-CoV-2 variants and postvaccination antibody testing continues be essential in determining possible standardization of SARS-CoV-2 vaccines regimens.

Objective: To study clinical and immunological characteristics of depressive patients with high clinical risk of schizophrenia.Materials and methods: We examined 30 depressive patients with attenuated positive symptoms (APS), which indicates a clinically high risk of schizophrenia, 20 depressive patients without APS and 27 healthy volunteers with no mental disorders. APS identified according to the presence of three or more scores on at least one of the following items on the Scale of Prodromal Symptoms (SOPS) positive symptoms subscale: P1 (Unusual thought content/Delusional ideas), P2 (Suspiciousness/Persecutory ideas) and P4 (Perceptual abnormalities/Hallucinations). The psychometric assessment was carried out on the Hamilton Depression Rating Scale (HDRS), SOPS, and the Scale for Assessment of Negative Symptoms (SANS). The activity of leukocyte elastase (LE) and α1-proteinase inhibitor (α1-PI), the autoantibodies to neoantigens S100B and myelin basic protein, and the ratio of LE and α1-PI activity or Leukocyte Inhibitory Index (LII) were determined. Results: The activity of inflammatory markers LE and α1-PI was increased in patients in both clinical groups compared with controls. In the total group of patients, the associations between LII and the score on the positive subscale SOPS, and between LII and the score on the negative subscale SOPS and SANS scale with the most pronounced association with the SANS subscales «Affective Flattening or Blunting» and «Alogia» were established. Conclusion: The identified correlations between immune response features and positive and negative symptoms in depressive patients may have prognostic value for establishing a high risk of schizophrenia.

Bone marrow and the central nervous system are both protected by bone. The two systems are interconnected not only structurally but also functionally. In both systems specialized cells communicate through synapses. There exists a tridirectional communication within the neuroimmune network, including the hormonal system, the immune system, and the nervous system. Bone marrow is a priming site for T cell responses to blood-borne antigens including those from the central nervous system. In cases of auto (self) antigens, the responses lead to immune tolerance while in cases of neo (non-self) antigens, the responses lead to neoantigen-specific T cell activation, immune control, and finally to the generation of neoantigen-specific immunological memory. Bone marrow has an important function in the storage and maintenance of immunological memory. It is a multifunctional and very active cell-generating organ, constantly providing hematopoiesis and osteogenesis in finely-tuned homeostasis. Clinical perspectives include mesenchymal stem cell transplantation for tissue repair within the central nervous system.

An autoimmune condition known as Systemic Lupus Erythematosus (SLE) affects several systems and manifests itself in a variety of ways. It is far more common among young women who are fertile.It has been demonstrated that a mix of environmental and genetic variables may trigger immunological responses, triggering T and B cells, and leading the B cells to overproduce pathogenic autoantibodies and dysregulate cytokines, which ultimately result in harm to many organs and tissues. One feature of SLE is the presence of antibodies against cytoplasmic and nuclear antigens. An autoimmune illness is also type 1 diabetes. β-cell antibodies (Ab) and other antibodies that cause the autoimmune death of the pancreatic β-cells, which make insulin, are part of the multifactorial pathophysiology of type 1 diabetes mellitus (T1DM).Immunosuppression is the therapy for systemic lupus erythematosus (SLE), and diabetes itself compromises immunity, making infections more opportunistic. We came across an unusual instance of a patient with SLE, T1DM, hypothyroidism on immunosuppression who subsequently acquired pulmonary TB.Key phrase: Autoimmune diseases such as type 1 diabetes mellitus (T1DM) and Systemic Lupus Erythematosus (SLE).

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) outbursts began at the end of 2019, which imposed a serious crisis on public health and the economy all over the world. To date, there is no antiviral drug available for SARS-CoV-2, and hence vaccination is the most preferred method to prevent people from getting attacked by this virus, especially for those who are at high risk. To counter coronavirus-2, there are various types of vaccines, which are being used, such as live attenuated vaccines, killed or inactivated vaccines, recombinant vaccines, mRNA vaccines, recombinant vector vaccines, and DNA vaccines. Novavax data shows that the vaccine is effective against severe diseases caused by B.1.351. The Pfizer-BioNTech and AstraZeneca vaccines show evidence of some protection against P.1. Due to the immune response, the Human body can recognize and protect itself against harmful foreign substances such as bacteria, viruses, and microorganisms. The immune system protects our body from these harmful substances by identifying them as antigens. Virus-infected cells release many chemicals such as chemokines and cytokines for the initiation of immune response. To control the pandemic situation, herd immunity is required by the immunization of a critical mass of the world population at once. In this review article, we have made an analysis of the immune response of the human body to SARS-CoV-2 infection, different types, and modes of action of SARS-CoV-2 vaccines along with the current status of vaccines.