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[Display omitted] The recent ongoing outbreak of coronavirus disease 2019 (COVID-19), still is an unsolved problem with a growing rate of infected cases and mortality worldwide. The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is targeting the angiotensin-converting enzyme 2 (ACE2) receptor and mostly causes a respiratory illness. Although acquired and resistance immunity is one of the most important aspects of alleviating the trend of the current pandemic; however, there is still a big gap of knowledge regarding the infection process, immunopathogenesis, recovery, and reinfection. To answer the questions regarding "the potential and probability of reinfection in COVID-19 infected cases" or "the efficiency and duration of SARS-CoV-2 infection-induced immunity against reinfection" we critically evaluated the current reports on SARS-CoV-2 immunity and reinfection with special emphasis on comparative studies using animal models that generalize their finding about protection and reinfection. Also, the contribution of humoral immunity in the process of COVID-19 recovery and the role of ACE2 in virus infectivity and pathogenesis has been discussed. Furthermore, innate and cellular immunity and inflammatory responses in the disease and recovery conditions are reviewed and an overall outline of immunologic aspects of COVID-19 progression and recovery in three different stages are presented. Finally, we categorized the infected cases into four different groups based on the acquired immunity and the potential for reinfection. In this review paper, we proposed a new strategy to predict the potential of reinfection in each identified category. This classification may help to distribute resources more meticulously to determine: who needs to be serologically tested for SARS-CoV-2 neutralizing antibodies, what percentage of the population is immune to the virus, and who needs to be vaccinated. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are emerging pollutants with diverse sizes in aquatic environments. This paper investigates the toxicity of micron- and nano-scale polystyrene (50 μm, 5 μm, 0.5 μm) loaded with 2-hydroxy-4-methoxy-benzophenone (BP-3) and ciprofloxacin (CIP) by eight biomarker responses in mussels, perna viridis. The mussels were exposed to MPs and chemicals for 7 days before 7 days of depuration. Eight biomarkers were measured to determine biotoxicity over time by using the weighted integrated biomarkers index evaluation (EIBR). Mussels exposed to MPs on a daily basis demonstrated a cumulative toxic effect. The toxicity of MPs for mussels was inversely related to the size at which they can be ingested. Then toxicity was reversed when exposure was halted. EIBR mold has shown a significant difference in the biotoxicity of each biological level under different exposure scenarios. In general, the mussel toxicity influenced by BP-3 and CIP exposure without an adsorbent was insignificant. MPs laden with them increased the toxicity of mussels. Under condition of lower concentration of ECs (Emerging contaminants), the presence of MPs as a component of a combined pollutant in water dominated the biotoxicity for mussels. The EIBR assessment further validated that the biotoxicity of mussels was size-dependent. Its application simplified the biomarkers' response index and enhanced the accuracy of evaluation by weighing on molecular, cellular and physiological level. Specifically, mussels were physiologically sensitive to nano-scale plastics, with nano-scale plastics causing a higher level of cellular immunity destruction and genotoxicity than micron-scale plastics. Enzymatic antioxidant systemswere upregulated based on size-differential plastics; however, the total antioxidant effect of non-enzymatic defenses appeared to be least affected by the size effect. [Display omitted] • Nano-scale plastics pose a greater threat to genotoxicity, immunotoxicity, and enzymatic antioxidant system. • MPs load BP-3 and CIP exposure causes a greater response than MPs exposure. • MPs transport chemicals into the internal circulatory to affect biological response. • EIBR corroborated increasing toxicity regulated by sizes of MPs. [ABSTRACT FROM AUTHOR]

Highlights: [•] The manuscript describes our view on hemocyte subsets, lineages and compartments. [•] The paper details the plasticity of plasmatocyte/macrophage lineages. [•] One of the main points of the paper is the regulation of the cell mediated immunity. [•] Phenotypic and functional changes upon effector cell differentiation are described. [•] The ontogenesis of the hematopoietic compartments is presented. [ABSTRACT FROM AUTHOR]

Evidence is accumulating that exposure to human immunodeficiency virus (HIV) can lead to an increased resistance or immunity to subsequent infection. A multirisk model that permits either induced immunity or infection to develop after heterosexual inoculation with HIV is shown to be compatible with a wide spectrum of disparate male-to-female transmission data.When the model is applied to time-dependent, HIV-seroprevalence data, the probability that an unexposed woman would remain unexposed after an unprotected contact with an infected man was estimated to be greater than 0.95 on the average. Thus, it would require at least 14 unprotected sexual contacts with HIV-infected men for 50% of an unexposed cohort of women to become exposed to the virus. This suggests that there is a low probability that HIV virions will be found to have penetrated the mucosal barriers of the reproductive tract after a contact.The model also predicts, that the average woman whose mucosal barriers have been breached by HIV has a significant probability of developing immunity to the virus rather than infection. Modelling data for a cohort of unexposed Nairobi women leads to the prediction that the probability of acquiring induced immunity per contact is about 60% of the probability of acquiring the disease per contact.The modelling results also predict that those who had developed resistance to HIV run the small, but significant risk of becoming infected nonetheless by continuing high-risk behavior. For the common contact rate of ten per month, the modelling predicts that the HIV-transmission risk per contact for unexposed women in the Nairobi cohort is SHAPE="SOL" ALIGN="C" STYLE="S">1178 while the transmission risk for the cohort''s immunized women is SHAPE="SOL" ALIGN="C" STYLE="S">11548. These numbers suggest that HIV infection is difficult to transmit through heterosexual intercourse on the average and that male-to-female HIV-transmission risk per contact for African women lies between SHAPE="SOL" ALIGN="C" STYLE="S">1178 and SHAPE="SOL" ALIGN="C" STYLE="S">11548.Direct confirmation of the predictions in the last paragraph has been subsequently observed in two completely independent studies. The Nairobi research team recently reported that a notable number of Nairobi prostitutes previously identified to be members of the HIV-resistant group became infected nonetheless. Second, in a study of 174 sexually monogamous, discordant couples in Rakai, Uganda reporting contacts rates of nine to ten per month, the male-to-female HIV-transmission risk per contact was found to be SHAPE="SOL" ALIGN="C" STYLE="S">1769 by direct measurement, a value that falls between the above limits of SHAPE="SOL" ALIGN="C" STYLE="S">1178 and SHAPE="SOL" ALIGN="C" STYLE="S">11548 predicted by the modelling. Thus, a second major prediction of this paper has been directly confirmed, and induced immunity to HIV is limited and not absolutely protective.Circumstantial evidence suggests that the induced immunity to HIV predicted by the model could be generated and/or initiated by nonspecific innate immune responses, specific immunological responses, including IgA-mediated mucosal immunity and cytotoxic T lymphocytes (CTL) immunity, or some combination of the above. It is suggested here, that a decrease in the ability of HIV virions to penetrate the protective mucus layer of the reproductive tract may be a prerequisite, cofactor, or the principle cause of the induced immunity or resistance demonstrated to exist in this paper. The value of the probability that induced immunity to HIV will develop after a contact is shown to be a sensitive function of the woman''s human leucocyte antigen (HLA) supertype profile. [Copyright &y& Elsevier]

Cyclophosphamide (CP) is a cytotoxic drug that can suppress both humoral and cellular immunity. Combining traditional medicinal herbs and chemotherapy drugs are used to improve immunity and quality of life performance status. In this paper, the effects of plant extracts, active components and their derivatives on immunosuppression of CP are discussed. Appropriate keywords were used to search through PubMed, Google Scholar, and Sciverse. All relevant results published from 1990 to date were chosen for final review. Over 50 references were found in which plant extracts, active components and their derivatives have been tested for their immune protective effects against CP-induced immune toxicity. Although there are several plants shown to be effective in animal models, no study was carried out on human subjects. According to the results; we can claim that plants and their active ingredients are good candidates for alternative adjuvant chemotherapy in reducing the immunotoxicity of CP. [ABSTRACT FROM AUTHOR]

The bursa of Fabricius, the acknowledged central humoral immune organ, plays a vital role in B lymphocyte differentiation. However, there are few reports of the molecular basis of the mechanism on immune induction and potential antitumor activity of bursal-derived peptides. In this paper, a novel bursal-derived pentapeptide-II (BPP-II, MTLTG) was isolated and exerted immunomodulatory functions on antibody responses in vitro. Gene microarray analyses demonstrated that BPP-II regulated expression of 2478 genes in a mouse-derived hybridoma cell line. Immune-related gene ontology functional procedures were employed for further functional analysis. Furthermore, the majority of BPP-II-regulated pathways were associated with immune responses and tumor processes. Moreover, BPP-II exhibited immunomodulatory effects on antigen-specific immune responses in vivo, including enhancement of avian influenza virus (H9N2 subtype)-specific antibody and cytokine production and modification of T cell immunophenotypes and lymphocyte proliferation. Finally, BPP-II triggered p53 expression and stabilization and selectively inhibited tumor cell proliferation. These data identified the multifunctional factor, BPP-II, as a novel biomaterial representing an important linking between the humoral central immune system and immune induction, including antitumor. Information generated in this study elucidates further the mechanisms involved in humoral immune system and represents the potential basis of effective immunotherapeutic strategies for treating human tumors and immune improvement. [ABSTRACT FROM AUTHOR]

Abstract: LEI/L-DNase II is the key protein of a caspase-independent pathway activated by serine proteases. LEI (Leukocyte elastase inhibitor), L-DNase II precursor, is a member of the clade B serpins (also called serpin b1). In its native conformation it inhibits several intracellular proteases and has an anti-apoptotic activity. Following a metabolic stress and the increase of protease activity in the cell, LEI is cleaved and transformed into L-DNase II (LEI-derived DNase II). This transformation is due to a conformational modification that exposes a nuclear localization signal and an endonuclease active site. In this paper we show that LEI can bind the exportin Crm1, and we identify on LEI a nuclear export signal involved in the control of LEI/L-DNase II nuclearization in healthy cells. Point mutation of this site increases the accumulation of the molecule in the nucleus and triggers cell death. [Copyright &y& Elsevier]

Dietary fish oil has immunomodulatory effects that are partly mediated by its effects on cytokine secretion. In this paper, we examine whether dietary fish oil has different effects on cytokine secretion by T cells and macrophages. Female BalbC mice were fed diets supplemented with 18% fish oil + 2% corn oil or 20% corn oil. Concanavalin A (ConA)- and LPS-induced TNF-alpha and IL-10 secretion by splenocytes was examined using ELISA. Dietary fish oil decreased ConA induced-, but increased LPS-induced, TNF-alpha and IL-10 secretion by total murine splenocytes. Dietary fish oil increased the number of splenocytes secreting TNF-alpha and IL-10, following stimulation with LPS, by 123 and 38%, respectively, but did not affect cytokine secretion by each cell, as determined using enzyme-linked immunospot. Spleens from mice fed the fish oil diet had over 2-fold higher proportion of macrophages with high expression of CD11b than spleens from mice fed the corn oil diet. In addition, fish oil increased the proportion of total and CD11b(+) splenocytes that expressed the LPS receptor complex molecules, CD14 and toll-like receptor (TLR)4/myeloid differentiation factor-2 (MD-2), by 85 and 28%, respectively. The increased proportion of macrophages expressing the LPS receptor complex molecules, CD14 and TLR4/MD-2, in spleens from mice fed the fish oil diet may explain the increased number of cells that secreted the cytokines after LPS stimulation. [ABSTRACT FROM AUTHOR]

In post-natal life the inflammatory response is an inevitable consequence of tissue injury. Experimental studies established the dogma that inflammation is essential to the establishment of cutaneous homeostasis following injury, and in recent years information about specific subsets of inflammatory cell lineages and the cytokine network orchestrating inflammation associated with tissue repair has increased. Recently, this dogma has been challenged, and reports have raised questions on the validity of the essential prerequisite of inflammation for efficient tissue repair. Indeed, in experimental models of repair, inflammation has been shown to delay healing and to result in increased scarring. Furthermore, chronic inflammation, a hallmark of the non-healing wound, predisposes tissue to cancer development. Thus, a more detailed understanding in mechanisms controlling the inflammatory response during repair and how inflammation directs the outcome of the healing process will serve as a significant milestone in the therapy of pathological tissue repair. In this paper, we review cellular and molecular mechanisms controlling inflammation in cutaneous tissue repair and provide a rationale for targeting the inflammatory phase in order to modulate the outcome of the healing response.Journal of Investigative Dermatology (2007) 127, 514–525. doi:10.1038/sj.jid.5700701 [ABSTRACT FROM AUTHOR]

Abstract: Hydroxyapatite (HA) is widely used to coat metal parts in order to improve their biocompatibility. Analysis of retrieved tissues associated with failed implants, suggest that phagocytosis of HA wear debris by monocytes/macrophages might provide a potent stimulus for the release of a variety of cytokines. Phagocytosis involved a large variety of cellular receptors like toll-like receptors that results in activation of the transcriptional nuclear factor-κB (NF-κB) via a cell-signalling pathway. In the present paper, we aimed to evaluate the role of the toll-like receptor 4 (TLR4) in the production of inflammatory cytokines induced by HA particles using TLR4+ and TLR4− peritoneal macrophages. We investigated the production of TNF-α and the activation of the nuclear transcription factor NF-κB. Our data clearly show for the first time that the production of TNF-α by macrophages exposed to HA particles was TLR4 dependent but not the activation of NF-κB. All these results open future therapies to reduce the inflammatory response induced by HA biomaterials. [Copyright &y& Elsevier]

Abstract: The hallmark of fibrosis is the excessive accumulation of collagen. The deposited collagen contains increased pyridinoline cross-link levels due to an overhydroxylation of lysine residues within the collagen telopeptides. Lysyl hydroxylase 2b (LH2b) is the only lysyl hydroxylase consistently up-regulated in several forms of fibrosis, suggesting that an enhanced LH2b level is responsible for the overhydroxylation of collagen telopeptides. The present paper reports the effect of profibrotic cytokines on the expression of collagen, lysyl hydroxylases and lysyl oxidase in normal human skin fibroblasts, as well as the effect on pyridinoline formation in the deposited matrix. All three isoforms of TGF-β induce a substantial increase in LH2b mRNA levels, also when expressed relatively to the mRNA levels of collagen type I α2 (COL1A2). The TGF-β isoforms also clearly influence the collagen cross-linking pathway, since higher levels of pyridinoline cross-links were measured. Similar stimulatory effects on LH2b/COL1A2 mRNA expression and pyridinoline formation were observed for IL-4, activin A, and TNF-α. An exception was BMP-2, which has no effect on LH2b/COL1A2 mRNA levels nor on pyridinoline formation. Our data show for the first time that two processes, i.e., up-regulation of LH2b mRNA levels and increased formation of pyridinoline cross-links, previously recognized to be inherent to fibrotic processes, are induced by various profibrotic cytokines. [Copyright &y& Elsevier]

Abundant evidence suggests that Treponema pallidum (T.p.) escapes humoral immune defence despite the host produces antibodies early in the infection. Since the serologic responses in syphilis have been studied in detail this paper focuses on the cellular immune mechanisms. For this purpose the leukocyte migration inhibition was investigated in 17 patients in different stages of syphilis. Leukocyte migration inhibition assay was performed before, and 7 days, 3 weeks, 2 mo, and 1 yr after start of treatment. Ultrasonicated T.p. were used as antigen corresponding to 5 × 106 to 2 × 107 Treponema pallida per ml. Controls without antigen, with addition of Concanavalin A instead of T.p. and using cells of normal volunteers were run. There was no leukocyte migration inhibition before treatment, suggesting nonexistent or depressed cellular immunity in the untreated syphilitic patient. Significant leukocyte migration inhibition, however, was observed as early as 2 days after start of treatment, being most pronounced after 1 week. Hypothetical circulating blocking factors for cellular immune reactions might be present in the untreated syphilitic patient, which become abolished after therapy. Since stimulation with Con A of syphilitic leukocytes gave normal results even before treatment in the syphilitic patient, there might be a specific block of leukocyte migration inhibition against T.p. [ABSTRACT FROM AUTHOR]

From February to August 2007 the effect of rearing system (confined (C) v. free ranging (FR)) and season (spring v. summer) was evaluated on behaviour, immune and blood parameters and beef production (experiment 1). From February to August 2008, the effect of rearing system was only evaluated on beef production (experiment 2). A total of 12 Podolian young bulls were used each year. They were slaughtered at 18 and 15 months of age in 2007 and 2008, respectively. Herbage mass and pasture composition were monitored during the 2 years. Pasture availability, in terms of herbage mass and composition, as well as its seasonal development, was similar in the 2 years. In the first experiment, FR animals spent more time walking (P < 0.05), feeding (P < 0.001) and standing (P < 0.01) and showed a lower number of agonistic (P < 0.05) and non-agonistic social interaction than C animals (P < 0.01). Significant lower concentrations of serum urea nitrogen (P < 0.001) and creatinine (P < 0.10) in FR animals indicated a lower protein nutritional status due to inadequate protein availability at pasture. As a consequence, average daily gains (P < 0.05), slaughter weight (P < 0.05) and body condition score (P < 0.01) were lower in grazing animals as compared with C bulls. Cellular immune responsiveness was higher in FR animals (P < 0.05). Similarly, antibody titre to keyhole limpet hemocyanin was higher in FR bulls at the 2nd and 3rd month after antigen injection (P < 0.05), whereas it tended to be higher at the 4th month (P < 0.10). In both experiments, grazing negatively affected meat colour in terms of lightness. Eighteen-month-old bulls also showed lower final weight, weight gain and body conditions when kept outdoor: a possible consequence of nutrient deficits, as suggested by the metabolic status of FR animals. The same animals, however, benefited from FR in terms of natural behaviour expression and immune responsiveness. When the experiment was replicated the subsequent year, on animals slaughtered at 15 months of age, no differences between the performances of FR and C animals were detected. The earlier slaughter age system was also proportionally less dependent on external inputs as grazing was not extended to the dry season when herbage mass availability was lower. [ABSTRACT FROM AUTHOR]

This article presents information about current research in the field of dermatology. According to a research paper published in a 2004 issue of the "British Journal of Dermatology," envelope proteins of the human endogenous retroviruses family are expressed in human normal, psoriatic and atopic skin by immunostaining and western blotting and that their expressions are regulated by ultra violet irradiation. Another study published in a 2004 issue of the "British Journal of Dermatology," looked at which T cell attracting chemokines are involved in allergic contact dermatitis models in mice which differ in their cytokine expression profiles.