Reverse Genetics Applied to Immunobiology of Tumor Necrosis Factor, a Multifunctional Cytokine.

Tumor necrosis factor (TNF) is one of many cytokines - protein molecules responsible for communication between the cells of immune system. TNF was discovered and given its grand name because of its striking antitumor effects in experimental systems, but its main physiological functions in the context of whole organism turned out to be completely unrelated to protection against tumors. This short review discusses "man-made" mouse models generated by early genome-editing technologies, which enabled us to establish true functions of TNF in health and certain diseases as well as to unravel potential strategies for improving therapy of TNF-dependent diseases.

Will Peptides Help to Stop COVID-19?

Peptides are widely used for the diagnostics, prevention, and therapy of certain human diseases. How useful can they be for the disease caused by the SARS-CoV-2 coronavirus? In this review, we discuss the possibility of using synthetic and recombinant peptides and polypeptides for prevention of COVID-19 via blocking the interaction between the virus and its main receptor ACE2, as well as components of antiviral vaccines, in particular, against new emerging virus variants.

Modulation of bioavailability of proinflammatory cytokines produced by myeloid cells.

In spite of successful therapeutic neutralization of proinflammatory cytokines in several autoimmune diseases, such therapy is not entirely free of side effects. The main reason relates to the fact that cytokine signaling may have protective components that need to be spared. Several approaches to achieve a less damaging cytokine inhibition are being explored.

Can we design a better anti-cytokine therapy?

Cytokine neutralization is successfully used for treatment of various autoimmune diseases and chronic inflammatory conditions. The complex biology of the two well-characterized proinflammatory cytokines TNF and IL-6 implicates unavoidable consequences when it comes to their global blockade. Because systemic cytokine ablation may result in unwanted side effects, efforts have been made to develop more specific cytokine inhibitors, which would spare the protective immunoregulatory functions of a given cytokine.

Making anti-cytokine therapy more selective: Studies in mice.

Cytokines are involved in a wide range of functions shaping the normal immune response, yet inflammatory changes in the immune system due to dysregulated cytokine signaling may lead to the induction of autoimmunity. Cytokine inhibitors have revolutionized the treatment of many autoimmune diseases in recent years. Systemic cytokine ablation, however, is often associated with the development of adverse side effects and some patients simply do not respond to therapy.

Cell-type-restricted anti-cytokine therapy: TNF inhibition from one pathogenic source.

Overexpression of TNF contributes to pathogenesis of multiple autoimmune diseases, accounting for a remarkable success of anti-TNF therapy. TNF is produced by a variety of cell types, and it can play either a beneficial or a deleterious role. In particular, in autoimmunity pathogenic TNF may be derived from restricted cellular sources.

Inflammation-induced formation of fat-associated lymphoid clusters.

Fat-associated lymphoid clusters (FALCs) are a type of lymphoid tissue associated with visceral fat. Here we found that the distribution of FALCs was heterogeneous, with the pericardium containing large numbers of these clusters. FALCs contributed to the retention of B-1 cells in the peritoneal cavity through high expression of the chemokine CXCL13, and they supported B cell proliferation and germinal center differentiation during peritoneal immunological challenges.

Experimental applications of TNF-reporter mice with far-red fluorescent label.

This chapter provides protocols for in vitro and in vivo analysis of TNF-producing cells from a novel TNF reporter mouse. In these transgenic mice, genetic sequence encoding far-red reporter protein Katyushka (FRFPK) was placed under control of the same regulatory elements as TNF, thus providing the basis for detection, isolation, and visualization of TNF-producing cells.

Cellular source and molecular form of TNF specify its distinct functions in organization of secondary lymphoid organs.

Secondary lymphoid organs provide a unique microenvironment for generation of immune responses. Using a cell type-specific conditional knockout approach, we have dissected contributions of tumor necrosis factor (TNF) produced by B cells (B-TNF) or T cells (T-TNF) to the genesis and homeostatic organization of secondary lymphoid organs. In spleen, lymph nodes and Peyer patches, the cellular source of TNF, and its molecular form (soluble versus membrane-bound) appeared distinct.

ELPylated anti-human TNF therapeutic single-domain antibodies for prevention of lethal septic shock.

Tumour necrosis factor (TNF) is a major pro-inflammatory cytokine involved in multiple inflammatory diseases. The detrimental activity of TNF can be blocked by various antagonists, and commercial therapeutics based upon this principle have been approved for treatment of diseases including rheumatoid arthritis, Crohn's disease and psoriasis. In a search for new, improved anti-inflammatory therapeutics we have designed a single-domain monoclonal antibody (V(H) H), which recognizes TNF.

Lymphotoxin beta receptor signaling in intestinal epithelial cells orchestrates innate immune responses against mucosal bacterial infection.

Epithelial cells provide the first line of defense against mucosal pathogens; however, their coordination with innate and adaptive immune cells is not well understood. Using mice with conditional gene deficiencies, we found that lymphotoxin (LT) from innate cells expressing transcription factor RORgammat, but not from adaptive T and B cells, was essential for the control of mucosal C. rodentium infection.

Accelerated thymic atrophy as a result of elevated homeostatic expression of the genes encoded by the TNF/lymphotoxin cytokine locus.

TNF, lymphotoxin (LT)-alpha, LT-beta and LIGHT are members of a larger superfamily of TNF-related cytokines that can cross-utilize several receptors. Although LIGHT has been implicated in thymic development and function, the role of TNF and LT remains incompletely defined. To address this, we created a model of modest homeostatic overexpression of TNF/LT cytokines using the genomic human TNF/LT locus as a low copy number Tg.

Transglutaminase-catalyzed covalent multimerization of Camelidae anti-human TNF single domain antibodies improves neutralizing activity.

Tumor necrosis factor (TNF) plays an important role in chronic inflammatory disorders, such as Rheumatoid Arthritis and Crohn's disease. Recently, monoclonal Camelidae variable heavy-chain domain-only antibodies (V(H)H) were developed to antagonize the action of human TNF (hTNF). Here, we show that hTNF-V(H)H does not interfere with hTNF trimerization, but competes with hTNF for hTNF-receptor binding.

Physiological functions of tumor necrosis factor and the consequences of its pathologic overexpression or blockade: mouse models.

TNF is an exciting cytokine which has helped to establish many paradigms in immunology. Although TNF itself has found only very limited use in the clinic, anti-cytokine therapy, which targets this single molecule, has enjoyed astounding success in treatment of a growing number of human diseases. However, since TNF mediates unique physiologic functions, in particular those related to host defense, TNF blockade may result in unwanted consequences.

Novel tumor necrosis factor-knockout mice that lack Peyer's patches.

We generated a novel tumor necrosis factor (TNF) null mutation using Cre-loxP technology. Mice homozygous for this mutation differ from their "conventional" counterparts; in particular, they completely lack Peyer's patches (PP) but retain all lymph nodes. Our analysis of these novel TNF-knockout mice supports the previously disputed notion of the involvement of TNF-TNFR1 signaling in PP organogenesis.

Distinct and nonredundant in vivo functions of TNF produced by t cells and macrophages/neutrophils: protective and deleterious effects.

Tumor necrosis factor (TNF, TNFalpha) is implicated in various pathophysiological processes and can be either protective, as in host defense, or deleterious, as in autoimmunity or toxic shock. To uncover the in vivo functions of TNF produced by different cell types, we generated mice with TNF ablation targeted to various leukocyte subsets. Systemic TNF in response to lipopolysaccharide was produced mainly by macrophages and neutrophils.