Measurement Of Delayed-type Hypersensitivity Research Articles

Long Term Cell Immune Response to COVID-19 Vaccines Assessment Using a Delayed-Type Hypersensitivity (DTH) Cutaneous Test.

Objective: As we progress with mass vaccination against SARS-CoV-2, there are key questions about the immunogenicity of COVID-19 vaccines that still are not answered. Conventional methods to measure cellular immune responses are complex and expensive in a pandemic situation. Patients and methods: Forty healthy healthcare workers accepted to participate during the vaccination schedule with a mRNA vaccine against SARS-CoV-2. Measurement of Delayed-Type Hypersensitivity (DTH) cutaneous response after intradermal test of protein S of SARS-CoV-2 at day 35 and day 200 was performed. At the same time, a specific anti-RBD IgG using a classic ELISA before vaccination, and on days 0, 35, and 200 was performed. Results: All 40 individuals had a positive DTH skin response at day 35, whereas 39 participants had a positive skin test at day 200. Moreover, although all 40 individuals showed a positive humoral response of specific IgG against spike protein at day 35, with most of them having significantly lower levels at day 200. Conclusion: DTH could be proposed as an ideal and easy method to predict cellular immunity response to mRNA vaccines 200 days after starting an immunization schedule with mRNA vaccine for COVID-19.

Coffea arabica Seed Extract Stimulate the Cellular Immune Function and Cyclophosphamide-induced Immunosuppression in Mice.

In this study, we investigate the immunostimulatory effects of alcoholic extract of the coffee seed on cell-mediated immune response and cyclophosphamide-induced (CP) immunosuppressed mice. The assessment of cellular immune function was carried out by the measurement of delayed-type hypersensitivity (DTH) response. According to the literature survey, cyclophosphamide has only suppressing effect on the lymphoid organ, white blood cell (WBC) and other parts of humoral immunity. Humoral immunity was assessed by the hemagglutination antibody titre. Mice were treated with three doses of extract (50, 150 and 250 mg/Kg body weight per os). Relative organ weight and WBC counts were also studied in these animals. At doses of 50 and 150, a significant increase (p < 0.05) in relative organ weight of spleen and thymus was observed but there was no effect on kidney and liver weights. WBC counts was also increased significantly (p < 0.001) in all doses of the plant extract. Coffea arabica extract elicited a significant (p < 0.001) increase in the DTH response at doses of 50 and 150 mg/Kg, but the change at higher dose of 250 mg/Kg was not statistically significant. In the HT test, plant extract also showed modulatory effect at all doses groups. Over all, coffee seed showed the stimulatory effect on cellular immune function and cyclophosphamide induced immunosuppression in mice.

Humoral and cellular immune response to a crude exo-antigen and purified keratinase of Microsporum canis in experimentally infected guinea pigs

In order to understand better the host–parasite relationship and to compare with previous observations in Microsporum canis naturally infected cats, the humoral and cellular immune responses to both a crude exo-antigen and a 31·5 kDa purified keratinase were evaluated in 12 M. canis experimentally infected guinea pigs. Humoral and cellular responses were assessed by ELISA from days 0 to 56 postinfection (PI) and by measurement of delayed-type hypersensitivity (DTH) responses on days 14 and 57 PI, respectively. Additionally, immunohistochemical staining was performed and demonstrated that the keratinase was produced in infected guinea pig skin, as previously reported in cats. Despite a marked interindividual variation, all the guinea pigs produced specific IgG to the crude exo-antigen from day 21 PI onwards, but no anti-keratinase IgG was detected. Strongly positive DTH responses to the exo-antigen were observed on both dates, whereas the keratinase elicited no and weak DTH on days 14 and 57 PI, respectively. These results are in agreement with those previously described for naturally infected cats, and indicate that the 31·5 kDa keratinase is not a major antigen in M. canis infection.

Intravenous Administration of RNA Suppresses the Induction of Delayed-type Hypersensitivity (DTH) to Tumor-associated Antigens.

Intravenous (iv) administration of protein antigens can induce relative tolerance to subsequent immunization with that antigen. We hypothesized that iv injection of RNA may also reduce cell-mediated immunity to antigens encoded by the RNA utilized. To test this hypothesis, we utilized the S1509a murine tumor system. CAF1 mice (H-2,a/d) were injected with I 00 g of total cellular RNA from the S1509a spindle cell tumor line (H-2a). Control animals were injected iv with saline. All mice were then immunized by subcutaneous injection of disrupted S1509a cells 3 times at 6-7 d intervals. One week after the last injection, syngeneic epidermal cells enriched for Langerhans cell content (eEC) by antibody and complement-mediated deletion of Thy-1-bearing cells were pulsed with a soluble extract of the S1509a cells as a source of tumor-associated antigens (TAA). eEC were then thoroughly washed and 7.5 x 105 injected into a hind footpad of each mouse. For negative controls, mice primed iv with RNA or saline alone prior to immunization were challenged with eEC not pulsed with TAA. Twenty-four hr footpad swelling was assessed as a measure of DTH. Mice given SI509a-derived RNA demonstrated a significantly smaller DTH response (p<0.001) compared to mice primed iv with saline. In a preliminary experiment, mice primed iv with unrelated RNA (derived from the NS cell line), S1509a RNA pretreated with RNase or saline pretreated with RNase prior to immunization failed to show a significantly inhibited DTH response compared to positive control mice primed iv with saline alone prior to immunization. These results demonstrate that iv administration of total cellular RNA from the S1509a tumor suppresses the induction of DTH to S1509a-derived TAA.

Humoral and cellular immune response to a crude exo-antigen and purified keratinase of Microsporum canis in experimentally infected guinea pigs

In order to understand better the host-parasite relationship and to compare with previous observations in Microsporum canis naturally infected cats, the humoral and cellular immune responses to both a crude exo-antigen and a 31.5 kDa purified keratinase were evaluated in 12 M. canis experimentally infected guinea pigs. Humoral and cellular responses were assessed by ELISA from days 0 to 56 postinfection (PI) and by measurement of delayed-type hypersensitivity (DTH) responses on days 14 and 57 PI, respectively. Additionally, immunohistochemical staining was performed and demonstrated that the keratinase was produced in infected guinea pig skin, as previously reported in cats. Despite a marked interindividual variation, all the guinea pigs produced specific IgG to the crude exo-antigen from day 21 PI onwards, but no anti-keratinase IgG was detected. Strongly positive DTH responses to the exo-antigen were observed on both dates, whereas the keratinase elicited no and weak DTH on days 14 and 57 PI, respectively. These results are in agreement with those previously described for naturally infected cats, and indicate that the 31.5 kDa keratinase is not a major antigen in M. canis infection.

Differential Regulation of Epidermal Cell Tumor-Antigen Presentation by IL-1α and IL-1β

IL-1 exists in two forms, termed IL-1alpha and IL-1beta, which exert similar effects in a number of biologic models. Recently, there have been reports of some differences in the activities of these two species in some systems. To address this issue with regard to Langerhans cells, Langerhans cell-enriched preparations of epidermal cells were treated with either IL-1alpha or IL-1beta before pulsing with S1509a tumor-associated antigens and subsequent use for immunization of naive mice to S1509a. While epidermal cells treated with 100 U IL-1beta per ml were able to induce protective tumor immunity (as indicated by the rejection of a subsequent tumor challenge with viable S1509a tumor cells), epidermal cells treated with 100 U IL-1alpha per ml failed to confer protective immunity. At 1000 U per ml, IL-1beta also inhibited the ability of epidermal cells to induce tumor immunity. To investigate the effects of the two IL-1 forms on elicitation of tumor immunity, naive mice were immunized against the S1509a tumor by s.c. injection of dead S1509a cells. Epidermal cells enriched for Langerhans cells were treated with either 100 U IL-1alpha or IL-1beta per ml before tumor-associated antigens-pulsing. Epidermal cells were then washed and injected into a hind footpad of tumor immune mice and 24 h footpad swelling was assessed as a measure of delayed-type hypersensitivity. Exposure to IL-1alpha led to suppressed elicitation of delayed-type hypersensitivity, whereas IL-1beta treated epidermal cells elicited a normal (100 U per ml) or enhanced (1000 U per ml) level of delayed-type hypersensitivity. Previous experiments indicated that the suppressive effects of IL-1alpha on induction of immunity may be mediated by TNF alpha. Therefore, the ability of IL-1alpha or IL-1beta to induce epidermal cell production of TNF alpha was assessed. IL-1alpha induced epidermal cells to secrete significantly higher amounts of TNF alpha protein compared with stimulation with IL-1beta. IL-1alpha and IL-1beta appear to differentially regulate epidermal cell antigen presenting capability.

The relationship between fatigue, psychological and immunological variables in acute infectious illness.

The aim of this paper is to explore the longitudinal relationships between physical and psychological symptoms and immunological factors following acute infective illnesses. Preliminary data from a prospective investigation of patients with serologically proven acute infectious illnesses due to Epstein-Barr virus (EBV), Ross River virus (RRV) or Q fever are reported. Patients were assessed within 4 weeks of onset of symptoms and then reviewed 2 and 4 weeks later. Physical illness data were collected at interview. Psychological and somatic symptom profiles were assessed by standardised self-report questionnaires. Cell-mediated immune (CMI) function was assessed by measurement of delayed-type hypersensitivity (DTH) skin responses. Thirty patients who had been assessed and followed over the 4-week period (including 17 patients with EBV, five with RRV and eight with Q fever) were included in this analysis. During the acute phase, profound fatigue and malaise were the most common symptoms. Classical depressive and anxiety symptoms were not prominent. Initially, 46% of cases had no DTH skin response (i.e. cutaneous anergy) indicative of impaired cellular immunity. Over the 4-week period, there was a marked improvement in both somatic and psychological symptoms, although fatigue remained a prominent feature in 63% of subjects. The reduction in reported fatigue was correlated with improvement in the DTH skin response (p = 0.001) and with improvement in General Health Questionnaire (GHQ) scores (p < 0.01). Acute infectious illnesses are accompanied by a range of nonspecific somatic and psychological symptoms, particularly fatigue and malaise rather than anxiety and depression. Although improvement in several symptoms occurs rapidly, fatigue commonly remains a prominent complaint at 4 weeks. Resolution of fatigue is associated with improvement in cell-mediated immunity.

Regulation of tumor antigen presentation by urocanic acid.

Urocanic acid (UCA) accumulates in the epidermis after deamination of histidine. UCA isomerizes from the trans to the cis form upon exposure to environmental UV radiation. Cis-UCA is immunosuppressive in several models. Topically applied cis-UCA was reported to enhance the cutaneous tumor yield in chronically UV-irradiated mice, suggesting involvement of cis-UCA in photocarcinogenesis. Since Langerhans cells (LC) are capable of presenting tumor-associated Ags (TAA) for primary and secondary tumor-immune responses, we examined the effects of trans- and cis-UCA on LC tumor Ag presentation in a model of immunity to the S1509a spindle cell tumor (H-2a). In this system, induction of immunity requires exposure of LC to granulocyte-macrophage CSF. Naive CAF1 (H-2(a/d)) mice were immunized against S1509a by injection with granulocyte-macrophage CSF-exposed and TAA-pulsed epidermal cells (EC), as assessed by growth inhibition of inoculated tumor cells. Incubation of EC in cis-, but not trans-UCA completely inhibited Ag presentation in this system. Neither histamine antagonists nor indomethacin reversed these effects of cis-UCA. The ability of trans- and cis-UCA to modulate EC presentation of TAA for secondary immune responses was also examined. EC were pulsed with TAA in vitro and then injected into hind footpads of tumor-immune mice. After 24 h, footpad swelling was assessed as a measure of delayed-type hypersensitivity. Incubation with cis-, but again not trans-UCA before TAA exposure significantly inhibited elicitation of delayed-type hypersensitivity. These data indicate that cis-UCA may be an important regulator of LC Ag-presenting function in tumor-immune responses, and thus may play a role in photocarcinogenesis.

IL-10 inhibits tumor antigen presentation by epidermal antigen-presenting cells.

IL-10 inhibits Langerhans cell (LC) Ag presentation to Th1 clones. As LC are capable of presenting tumor-associated Ags (TAA) for primary and secondary tumor immune responses, we examined the effect of IL-10 on LC Ag presentation in a model of immunity to the S1509a spindle cell tumor (H-2a). Because induction of immunity to S1509a requires exposure of LC to granulocyte-macrophage (GM)-CSF, this system also allowed us to study the regulatory interactions of GM-CSF and IL-10 on LC. Naive CAF1 (H-2a/d) mice could be immunized against S1509a by injection with GM-CSF-exposed and TAA-pulsed epidermal cells (EC) as assessed by inhibition of the growth of inoculated tumor cells. Incubation of EC in IL-10 before GM-CSF exposure completely inhibited Ag presentation in this system. Significantly, neither co-incubation of EC in IL-10 and GM-CSF (without preincubation in IL-10) nor IL-10 treatment after GM-CSF incubation was able to exert a down-regulatory effect. The ability of IL-10 to modulate EC presentation of TAA for a secondary immune response was also examined. EC were pulsed with TAA in vitro and then injected into a hind footpad of tumor-immune mice with 24 h swelling assessed as a measure of delayed-type hypersensitivity. Preincubation in IL-10 before TAA exposure significantly inhibited elicitation of delayed-type hypersensitivity with or without subsequent exposure to GM-CSF. Co-incubation of EC in IL-10 and GM-CSF or exposure to IL-10 after GM-CSF led to a normal response. These data indicate that IL-10 may serve as an important regulator of LC Ag-presenting function for tumor immune responses. IL-10 appears to specifically prevent the GM-CSF-induced maturation of LC Ag-presenting function when treatment with IL-10 occurs before exposure to GM-CSF but does not reverse the established mature state.

Chemokine expression in trinitrochlorobenzene-mediated contact hypersensitivity

The expression of the murine IP-10 and MCP-1 genes has been examined in the skin of mice during contact hypersensitivity reactions to the hapten trinitrochlorobenezene (TNCB). In both naive and passively sensitized animals, challenge with TNCB resulted in elevated expression of both genes as early as 4 h as detected by Northern hybridization analysis. Twenty-four hours after challenge, expression was markedly reduced in naive animals but remained elevated in sensitized animals. This prolonged expression of chemokine gene products correlates with the tissue swelling response generally used as a measure of delayed-type hypersensitivity (DTH) in this model and suggests that the continued expression of these genes results from the stimulation of hapten-specific T helper cells. Examination of cell type expression patterns by in situ hybridization using 3H-radiolabeled riboprobes confirmed the results of Northern hybridization experiments. Both genes were expressed predominantly in cells exhibiting the morphology of connective tissue fibroblasts, although the distribution of cells positive for IP-10 mRNA expression differed from that of cells expressing MCP-1 mRNA. IP-10 expression was localized almost exclusively to a population of connective tissue cells surrounding the fur follicle. MCP-1 expression was rarely found associated with fur follicles but instead was distributed throughout the dermis in cells embedded in the collagenous extracellular matrix. Surprisingly, neither endothelial cells lining the small vessels located deep within the dermis nor epidermal keratinocytes were positive under any of the conditions utilized in the present study. Expression of both IP-10 and MCP-1 has been previously reported in a variety of distinct cell types in vitro. The present results indicate that only a subset of the cell types with such potential are stimulated to express these chemokine genes in vivo during hapten-mediated DTH responses, implying the presence of subtle cell type- and tissue-specific control mechanisms.

Cell-mediated immunity assessed by Multitest CMI skin testing in infants and preschool children.

Two hundred twenty-one healthy children, from 6 months to 7 years of age, were tested for delayed-type hypersensitivity (DTH) by the Multitest CMI (cell-mediated immunity) (Merieux Institute, Miami). This device permits the simultaneous application of seven standardized recall antigens and a glycerol diluent control. Younger children were tested on the back and older children on the volar surface of the forearm. Only 6.8% of the children were anergic, and most of them (11/15) were female. The DTH responses were present for one or more antigens in 93% of the infants. The DTH responses increased tremendously during the second year of life and increased slowly thereafter. A relatively high incidence of positive reactions was found for three of the tested antigens--diphtheria toxoid (79%), tetanus toxoid (62%), and Proteus (57%), in children in the preschool years, and accounted for three fourths of all positive reactions. Much lower levels were found for Streptococcus (25%), Candida (16%), Trichophyton (5%), and tuberculin (4%). Measurement of DTH by the standardized Multitest CMI system seems to be a convenient and reliable tool for assessing CMI function in infants and small children. The tool permitted us to measure patterns of DTH responses from infancy onward in a healthy population and to develop index values in a normal reference population with which any tested preschool child can be compared.

Suppression of tuberculin hypersensitivity during influenza infection in mice

Tuberculin hypersensitivity was examined during acute influenza infection in mice. Employing the footpad test as a measure of delayed-type hypersensitivity, it was noted that tuberculin hypersensitivity was suppressed temporarily beginning on day 3 and continuing through days 10 to 16 following intranasal infection with influenza A/PR8. These changes occurred at a time when influenza virus was replicating in lung tissue. Suppression of footpad swelling was not detected when mice were administered live virus intravenously, were given Formalin-inactivated virus intranasally, or were immunized against influenza before intranasal infection. Transient reduction of total circulating lymphocytes also occurred during influenza infection but did not correlate with the duration of footpad suppression. Because this model system reproduces many of the alterations in immunological function reported to occur during influenza infection in humans, it should provide a useful tool for investigating mechanisms of influenza-induced immunosuppression.