Immune Response Regulation by Antigen Receptors' Clone-Specific Nonself Parts

Antigen-specificity measurements are the key to understanding T cell responses

Antigen-specific T cells play a central role in the adaptive immune response and come in a wide range of phenotypes. T cell receptors (TCRs) mediate the antigen-specificities found in T cells. Importantly, high-throughput TCR sequencing provides a fingerprint which allows tracking of specific T cells and their clonal expansion in response to particular antigens. As a result, many studies have leveraged TCR sequencing in an attempt to elucidate the role of antigen-specific T cells in various contexts. Here, we discuss the published approaches to studying antigen-specific T cells and their specific TCR repertoire. Further, we discuss how these methods have been applied to study the TCR repertoire in various diseases in order to characterize the antigen-specific T cells involved in the immune control of disease.

Is Formulary of Maranta Arundinacea Clarias Gariepinus (F-MaCg) a Potential Immunostimulant?

Background

External factors have the potential to act as immunostimulants in order to influence the body's protection from many foreign antigens. We intended to investigate the ethanol extract Formulary of F-MaCg effect as an immunostimulant.

Methods

A purely experimental with a completely randomized design was used on twenty-four white male rats. They were divided into four groups:1) G0 [given aquades (5 ml)]; 2) G1 [given F-MaCg-75 mg/gr BW (Body Weight)]; 3) G2 (F-MaCg -150 mg/gr plus Hepatitis B vaccine at the beginning and the end of treatment); and 4) G3 (F-MaCg -300 mg/gr BW plus hepatitis B vaccine at the end of treatment). The rat's spleen lymphocyte blast transformation was evaluated on the 15th and 37th days. Lymphocytes were examined using microtetrazolium assays. Optical Density (OD) was measured using an ELISA reader [493 nμ (nanomicro)]. Observation of lymphocyte viability by a counting chamber using a light microscope and trypan blue 1% before being cultured with Phytohaemoaglutinin.

Results

Lymphocyte cell viability in the hepatitis B vaccine-induced group on the 15th day showed the highest average value in the G2 (1,484/mcl of blood); on the 37th day, it was in G3 (1,578/mcl of blood). The proliferative activity of spleen lymphocytes indicated by the difference in the OD values of the four treatment groups was 0.467, 0.913, 1.619, and 1.473 nμ, respectively. Histological observations of the spleen showed differences at all given formulary dose concentrations.

Conclusion

F-MaCg could be an immunostimulant because of its ability to trigger a cellular immune response.

Molecular Bases of Protein Antigenicity and Determinants of Immunogenicity, Anergy, and Mitogenicity

BACKGROUND

The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on.

OBJECTIVE

Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness.

CONCLUSION

The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.

What Can We Learn from Research with Monoclonal Antibody 1F7?

1F7 is a monoclonal antibody that recognizes an idiotypic determinant expressed on primate antibodies binding to HIV-1 and hepatitis C proteins. This monoclonal antibody was used as a tool to dissect the immune response in humans infected with HIV-1 and hepatitis B. Furthermore, 1F7 was also used to manipulate the immune response against HIV-1 in macaques. The generation of a monoclonal antibody describing a network suggests similar antibodies could be developed as tools to dissect entangled networks in autoimmune diseases and allergic reactions. This review discusses the body of work done with 1F7 in the light of contemporary immunology.

In vitro co-culture model of human monocyte-derived dendritic cells and T cells to evaluate the sensitization of dinitrochlorobenzene

Exposure to sensitizer has been suggested to be hazardous to human health, evaluation the sensitization of sensitizer is particularly important and urgently needed. Dendritic cells (DCs) exert an irreplaceable function in immunity, and the T cell receptor (TCR) repertoire is key to ensuring immune response to foreign antigens. We hypothesized that a co-culture model of human monocyte-derived dendritic cells (Mo-DCs) and T cells could be employed to evaluate the sensitization of DNCB. An experimental model of DNCB-induced sensitization in rat was employed to examine alterations of cluster of differentiation CD103⁺ DCs and T cells. A co-cultured model of Mo-DCs and T cells was developed in vitro to assess the sensitization of DNCB through the phenotypic and functional alterations of Mo-DCs, as well as the TCR repertoire. We found that the CD103⁺ DCs phenotype and T-helper (Th) cells polarization altered in sensitization rats. In vitro, phenotypic alteration of Mo-DCs caused by DNCB were consistent with in vivo results, antigen uptake capacity of Mo-DCs diminished and capacity of Mo-DCs to prime T cell increased. Clones of the TCR repertoire and the diversity of TCR repertoire were enhanced, changes were noted in the usage of variable, joining, and variable-joining gene combinations. DNCB exposure potentiated alterations and characteristics of Mo-DCs and the TCR repertoire in a co-culture model. Such changes provided innovative ideas for evaluating sensitization of DNCB.

Searching for the Antioxidant, Anti-Inflammatory, and Neuroprotective Potential of Natural Food and Nutritional Supplements for Ocular Health in the Mediterranean Population

Adherence to a healthy diet offers a valuable intervention to compete against the increasing cases of ocular diseases worldwide, such as dry eye disorders, myopia progression, cataracts, glaucoma, diabetic retinopathy, or age macular degeneration. Certain amounts of micronutrients must be daily provided for proper functioning of the visual system, such as vitamins, carotenoids, trace metals and omega-3 fatty acids. Among natural foods, the following have to be considered for boosting eye/vision health: fish, meat, eggs, nuts, legumes, citrus fruits, nuts, leafy green vegetables, orange-colored fruits/vegetables, olives-olive oil, and dairy products. Nutritional supplements have received much attention as potential tools for managing chronic-degenerative ocular diseases. A systematic search of PubMed, Web of Science, hand-searched publications and historical archives were performed by the professionals involved in this study, to include peer-reviewed articles in which natural food, nutrient content, and its potential relationship with ocular health. Five ophthalmologists and two researchers collected the characteristics, quality and suitability of the above studies. Finally, 177 publications from 1983 to 2021 were enclosed, mainly related to natural food, Mediterranean diet (MedDiet) and nutraceutic supplementation. For the first time, original studies with broccoli and tigernut (chufa de Valencia) regarding the ocular surface dysfunction, macular degeneration, diabetic retinopathy and glaucoma were enclosed. These can add value to the diet, counteract nutritional defects, and help in the early stages, as well as in the course of ophthalmic pathologies. The main purpose of this review, enclosed in the Special Issue "Health Benefits and Nutritional Quality of Fruits, Nuts and Vegetables," is to identify directions for further research on the role of diet and nutrition in the eyes and vision, and the potential antioxidant, anti-inflammatory and neuroprotective effects of natural food (broccoli, saffron, tigernuts and walnuts), the Mediterranean Diet, and nutraceutic supplements that may supply a promising and highly affordable scenario for patients at risk of vision loss. This review work was designed and carried out by a multidisciplinary group involved in ophthalmology and ophthalmic research and especially in nutritional ophthalmology.

[Clonality analysis in practice]

Malignant lymphomas are derived from a common progenitor cell with a unique rearrangement of immunoglobulin or T‑cell receptor genes. Polymerase chain reaction (PCR)-based analyses allow detection of the clone and are an important adjunct for the diagnosis of difficult lymphoproliferations, e.g. for the discrimination of reactive versus malignant lesions. Further applications are detection of disease dissemination and evaluation of the clonal relationship of two lymphomas. However, clonality analysis is not a stand-alone test and must always be considered in context with clinical, histological and immunophenotypic data. For the correct use of clonality analysis, comprehensive knowledge of the biological basis, technical requirements and interpretation are needed in order to avoid incorrect conclusions.

A Novel Hypothesis for Original Antigenic Sin in the Severe Disease of SARS-CoV-2 Infection

In this hypothesis, we address the biological/immunological pathway leading to severe disease or death after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The underlying immune response is described with "original antigenic sin" (OAS) whereby previous infections influence the response to future virus encounters. We cite evidence for OAS-induced immunopathology in HIV-1 disease. We hypothesize that similar immune abnormalities can occur after infection with SARS-CoV-2. This hypothesis is supported by recent analysis of the antibodies in infected patients demonstrating serological and B cell abnormalities. The concept of symmetrical clonal regulation developed earlier for the immune network illustrates the pathway suggested by our hypothesis and may be helpful to develop strategies avoiding severe coronavirus disease 2019.

Linking autoantigen properties to mechanisms of immunity

Antigen-specific immunotherapies (ASIT) present compelling potential for introducing precision to the treatment of autoimmune diseases where nonspecific, global immunosuppression is currently the only treatment option. Central to ASIT design is the delivery of autoantigen, which parallels allergy desensitization approaches. Clinical success in tolerizing allergen-specific responses spans longer than a century, but autoimmune ASITs have yet to see an FDA-approved breakthrough. Allergens and autoantigens differ substantially in physicochemical properties, and these discrepancies influence the nature of their interactions with the immune system. Approved allergen-specific immunotherapies are typically administered as water soluble, neutrally charged protein fractions from 10 to 70 kDa. Conversely, autoantigens are native proteins that exhibit wide-ranging sizes, solubilities, and charges that render them susceptible to immunogenicity. To translate the success of allergen hyposensitization to ASIT, delivery strategies may be necessary to effectively format autoantigens, guide biodistribution, and engage appropriate immune mechanisms.

The Promise of Anti-idiotype Revisited

The promise of idiotype-based therapeutics has been disappointing forcing a new look at the concept and its potential to generate an effective approach for immunotherapy. Here, the idiotype network theory is revisited with regard to the development of efficacious anti-idiotype vaccines. The experience of polyclonal anti-Idiotype reagents in animal models as well as an understanding of the immune response in humans lends to the proposition that polyclonal anti-Idiotype vaccines will be more effective compared to monoclonal-based anti-Idiotype vaccines. This novel strategy can be adapted in Biotech-standard production of therapeutic antibodies.