Delayed-type Hypersensitivity Skin Responses Research Articles

Biochemical correlates of in vivo cell-mediated immune dysfunction in patients with depression: A preliminary report

We have previously demonstrated that at least 50% of patients with melancholia have impaired cell-mediated immunity (CMI) as assessed by delayed-type hypersensitivity (DTH) skin responses to a standardized battery of antigens. Hypercortisolaemia and increased circulating catecholamines both occur in patients with severe depressive disorders and each has been proposed as a possible mediator of observed immune abnormalities in patients with mood disorders. As part of a larger study, we collected 24 h urine samples from 28 patients with major depression and measured concentrations of urinary free cortisol (UFC), the noradrenaline metabolite dihydroxyphenylglycol (DHPG), adrenaline, and the dopamine metabolite DOPAC. CMI multitest skin testing revealed a reduced or absent response in 54% of subjects. Those with reduced DTH skin responses demonstrated increased urinary adrenaline ( P<0.02), with trends towards increased UFC ( P = 0.052) and increased DHPG ( P = 0.06). These differences could not be attributed to differences in age or depression severity. Correlational analyses demonstrated inverse associations between the extent of DTH responsiveness and 24 h levels of urinary adrenaline and DHPG, with similar trends evident for UFC and DOPAC. These results suggest that both circulating catecholamines and cortisol may play roles in the reduction of CMI in patients with severe depression.

Immunity to TCR peptides in multiple sclerosis. I. Successful immunization of patients with synthetic V beta 5.2 and V beta 6.1 CDR2 peptides.

Immunization with disease-associated TCR V region peptides is an effective treatment for experimental autoimmune encephalomyelitis. Myelin basic protein-specific T cells, which induce experimental autoimmune encephalomyelitis in many animal strains, may be important in the pathogenesis of multiple sclerosis. Myelin basic protein-specific T cell clones from some multiple sclerosis patients preferentially use TCR V genes from the V beta 5.2 and V beta 6.1 families. To assess the safety and immunogenicity of TCR V beta 5.2 and V beta 6.1 peptides, we injected 11 multiple sclerosis patients with varying doses of two synthetic peptides, TCR V beta 5.2(39-59) and V beta 6.1(39-59), encompassing the CDR2 region of these V gene families. Low doses (100 to 300 micrograms) of peptide induced T cell immunity in 7 of 11 patients to one or both peptides. Delayed type hypersensitivity skin responses to the peptides were observed in three of seven responders, and TCR peptide-specific Ab occurred in two of seven T cell responders. Low doses of TCR peptides produced no side effects and did not cause broad spectrum immunosuppression. Synthetic TCR V region peptides can induce T cell immunity safely in humans and may prove useful in treating human autoimmune diseases.

The behavioural, endocrine and leucocyte response of ewes to repeated removal of lambs before the age of natural weaning

Changes in the blood leucocyte population in response to psychological stressors could increase susceptibility to disease and be useful in the assessment of animal welfare. This paper examines the effect of repeated lamb removal on the blood leucocyte population of ewes and quantifies the behavioural and endocrine responses to the stressor. Twelve ewes which had given birth to twins, were placed in separate pens with their lambs. After 13 days, the lambs (14–19 days old) from one group of six ewes (treatment group) were removed from the pens and placed in a pen 11 m from the nearest ewe. After 3 h the lambs were moved back to their dam. The lambs then remained with their dam for 3 h before being removed for a second period of 3 h. This procedure was repeated for 23 days. A control group of six ewes remained with their lambs continuously for the 24-day experimental period. The removal of lambs produced behavioural changes in the ewes. These included: orientation towards the lamb, vocalization, raised head, erect ears, and decreased lying and sleeping behaviours. Although these changes were present over the 24-day experimental period, there were signs of habituation after 3 days of the treatment. The endocrine responses to lamb removal were less marked. Some ewes showed a plasma cortisol and β-endorphin response on Day 1 of lamb removal, but the mean responses were not statistically different from the control group. There was no obvious plasma prolactin response to the treatment. On Day 10 of lamb removal, the blood concentration of neutrophils in the treatment ewes had increased and the proportion of CD2 lymphocytes and T19 lymphocytes had decreased compared with that of control ewes. There were no significant differences between the treatment and control ewes in either the delayed type hypersensitivity skin responses to Dinitroflurobenzene or the humoral antibody responses to ovalbumin. These results indicate that ewes can show behavioural responses to a stressor, such as repeated lamb removal. However, this stressor had no significant effect on the endocrine and immune measurements studied.

Immunologic effects of national cholesterol education panel step-2 diets with and without fish-derived N-3 fatty acid enrichment.

Reductions in dietary fat, saturated fat, and cholesterol have been recommended to reduce the risk of heart disease in our society. The effects of these modifications on human cytokine production and immune responses have not been well studied. 22 subjects > 40 yr of age were fed a diet approximating that of the current American (14.1% of calories as saturated fatty acids, [SFA], 14.5% monounsaturated fatty acids [MUFA], 6.1% [n-6] polyunsaturated fatty acids [PUFA], 0.8% [n-3] PUFA, and 147 mg cholesterol/1,000 calories) for 6 wk, after which time they consumed (11 in each group) one of the two low-fat, low-cholesterol, high-PUFA diets based on National Cholesterol Education Panel (NCEP) Step 2 recommendations (4.0-4.5% SFA, 10.8-11.6% MUFA, 10.3-10.5% PUFA, 45-61 mg cholesterol/1,000 calories) for 24 wk. One of the NCEP Step 2 diets was enriched in fish-derived (n-3) PUFA (low-fat, high-fish: 0.54% or 1.23 g/d eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA] [121-188 g fish/d]) and the other low in fish-derived (n-3) PUFA (low-fat, low-fish [0.13% or 0.27 g/d EPA and DHA] [33 g fish/d]). Measurements of in vivo and in vitro indexes of immune responses were taken after each dietary period. Long-term feeding of low-fat, low-fish diet enriched in plant-derived PUFA increased blood mononuclear cell mitogenic response to the T cell mitogen Con A, IL-1 beta, and TNF production and had no effect on delayed-type hypersensitivity skin response, IL-6, GM-CSF, or PGE2 production. In contrast, the low-fat, high-fish diet significantly decreased the percentage of helper T cells whereas the percentage of suppressor T cells increased. Mitogenic responses to Con A and delayed-type hypersensitivity skin response as well as the production of cytokines IL-1 beta, TNF, and IL-6 by mononuclear cells were significantly reduced after the consumption of the low-fat, high-fish diet (24, 40, 45, 35, and 34%, respectively; P < 0.05 by two-tailed Student's t test except for IL-1 beta and TNF, which is by one-tailed t test). Our data are consistent with the concept that the NCEP Step 2 diet that is high in fish significantly decreases various parameters of the immune response in contrast to this diet when it is low in fish. Such alterations may be beneficial for the prevention and treatment of atherosclerotic and inflammatory diseases but may be detrimental with regard to host defense against invading pathogens.

Effect of Locally Administered Heparins on Delayed-Type Hypersensitivity Reactions

Inflammatory reactions involved in delayed-type hypersensitivity (DTH) are associated with extravascular coagulation and fibrin deposition. Heparin and other anticoagulants administered systemically inhibit DTH reactions but the direct effect of intradermally injected heparin on the development of DTH skin responses has not been reported. The effects of heparin on the DTH reaction elicited by ovalbumin (OVA) in guinea pigs 1-3 weeks after sensitization were examined. Unfractionated heparin, low affinity heparin (LAH; non-anticoagulant) and high affinity heparin (HAH; anticoagulant) were injected together with suboptimal amounts of OVA. Heparin and LAH enhanced skin induration, LAH (0.5 micrograms) by an average of 50% above that due to OVA alone at 24 h (p less than 0.01). In contrast, HAH (0.5 micrograms) significantly reduced skin induration at 24 h. Heparin and LAH also significantly increased cellular infiltration with LAH having the greater effect. At 4 h the infiltrate consisted mainly of neutrophils whereas at 24 h mononuclear cells predominated. Fibrin deposition, assessed both by immunohistology and quantitation of radioactive fibrin extracted from skin test sites, was increased by 30% when OVA was tested in the presence of LAH. Mast cell heparin released locally at sites of DTH has the potential to modulate these reactions in either a pro- or anti-inflammatory manner. This study is the first to demonstrate differences in the capacities of LAH and HAH to modulate cell-mediated inflammation.

Evaluation of immunity to feline infectious peritonitis in cats with cutaneous viral-induced delayed hypersensitivity

Delayed-type hypersensitivity (DTH)-like reactions to feline infectious peritonitis (FIP) virus (FIPV) were induced in the skin of nine cats that were asymptomatic after a previous challenge-exposure with FIPV. Four of the nine previously challenge-exposed cats were negative for virus-neutralizing antibodies against FIPV at the time of intradermal (ID) testing for DTH. Two other cats tested for DTH when acutely ill with clinical FIP did not have cutaneous DTH responses to FIPV. Gross skin reactions to FIPV injected ID were observed in six of nine asymptomatic cats (67%) at postintradermal inoculation hours (PIH) 24, 48, and/or 72. The reactions consisted of focal, 1–5-mm to 2.5-cm diameter indurated or semi-firm, nonerythematous, slightly raised nodules. Microscopically, DTH-like reactions were observed in biopsies taken from the FIPV-inoculated skin of asymptomatic cats at PIH 24 to 72. The lesions consisted of perivascular and diffuse dermal infiltrations by macrophages, lymphocytes, and polymorphonuclear leukocytes (PMN). The dermal infiltrates, which were maximal at PIH 48 or 72, were predominantly mixed inflammatory cells (five of nine cats) or PMN (four of nine cats) at PIH 24, but later were predominantly mononuclear cells (six of nine cats) or mixed inflammatory cells (two of nine cats) at PIH 72. Five of nine cats (56%) with positive DTH skin responses had increased survival times after lethal ID challenge-exposure with FIPV compared to mean survival times in FIPV-naive, non-immune control cats that were DTH-negative when ID challenge-exposed. Four of nine DTH-positive cats (44%) resisted an ID challenge-exposure dose of FIPV that was fatal in both control cats, and two of the four remaining DTH-positive cats survived a third challenge-exposure with highly lethal doses of FIPV given intraperitoneally. Four of the six DTH-positive cats (67%) that died after re-challenge and were necropsied had lesions of noneffusive FIP, suggesting that cellular immunity may also be involved in the pathogenesis of noneffusive disease, whereas both control cats and both DTH-negative cats with clinical disease succumbed to effusive FIP. Seemingly, DTH responses to FIPV can be associated with an increased level of resistance to disease; however, this state of immunity is variable and apparently can be lost with time in some cats.

Delayed-type hypersensitivity skin responses associated with feline infectious peritonitis in two cats

Two cats previously challenge-exposed and seropositive to feline infectious peritonitis virus (FIPV) were evaluated for delayed-type hypersensitivity (DTH) skin responses to intradermal FIPV. Before testing, cat 1 (FIP-resistant) had survived a severe experimental FIPV challenge-exposure and had remained asymptomatic, whereas cat 2 (FIP-susceptible) developed acute fulminant FIP after a considerably smaller virus challenge-exposure. Cat 1 developed a focal thickened plaque at the FIPV-injected skin site at 48 hours after injection. Histological examinations of serial punch biopsies from virus-inoculated skin revealed perivascular and diffuse dermal infiltrations of macrophages, lymphocytes and polymorphonuclear leucocytes which were maximal at 48 to 72 hours after injection. In contrast, cat 2 did not react grossly and showed only very mild dermal infiltrates at 72 hours after injection. The present findings of strong DTH responses to FIPV in a resistant cat and minimal responses in a cat with acute fulminant FIP suggest that certain in vivo cellular immune reactions may be associated with disease resistance.

Anti-Arthritic and Immunoregulatory Effects of TI-31 on Collagen-Induced Arthritis

TI-31 (TEI-3096, 6-p-chlorobenzyl-5H-2,3,6,7-tetrahydro-5,7-dioxo-thiazolo[3,2-a]pyrimidine) reduced bovine type II collagen-induced arthritis (CIA) in rats in a time- and dose-dependent manner. Oral TI-31 treatment in doses of 10 and 50 mg/kg daily for 7 days prior to collagen immunization depressed the development of arthritis. However, it had no obvious effect on CIA when administered daily for a 7-day or 28-day period after the immunization. This compound was also ineffective against the established arthritis. On the contrary, cyclophosphamide, dexamethasone, or ibuprofen strongly protected the animals from the development of arthritis and/or cured the established arthritis by these dose regimens. Both humoral and delayed-type hypersensitivity skin responses to bovine type II collagen were decreased in rats treated with TI-31 daily for 7 days before the induction of arthritis. These results suggest that TI-31 depresses CIA by regulating the immune response to collagen through a mechanism different from that of anti-inflammatory drugs or immunosuppressants.

Anti-arthritic and immunoregulatory effects of TI-31 on collagen-induced arthritis.

TI-31 (TEI-3096, 6-p-chlorobenzyl-5H-2,3,6,7-tetrahydro-5,7-dioxothiazolo[3,2-a]pyr imidine) reduced bovine type II collagen-induced arthritis (CIA) in rats in a time- and dose-dependent manner. Oral TI-31 treatment in doses of 10 and 50 mg/kg daily for 7 days prior to collagen immunization depressed the development of arthritis. However, it had no obvious effect on CIA when administered daily for a 7-day or 28-day period after the immunization. This compound was also ineffective against the established arthritis. On the contrary, cyclophosphamide, dexamethasone, or ibuprofen strongly protected the animals from the development of arthritis and/or cured the established arthritis by these dose regimens. Both humoral and delayed-type hypersensitivity skin responses to bovine type II collagen were decreased in rats treated with TI-31 daily for 7 days before the induction of arthritis. These results suggest that TI-31 depresses CIA by regulating the immune response to collagen through a mechanism different from that of anti-inflammatory drugs or immunosuppressants.

Specific depression of cell-mediated immunity in Malayan filariasis

The possible depression of cell-mediated immunity by long-term Brugia malayi infection in jirds (Meriones unguiculatus) was investigated. Different groups of infected jirds were sensitized with dinitrofluorobenzene, sheep red blood cells, Dirofilaria immitis adult antigens and B. malayi adult antigens. The 24-hour delayed type hypersensitivity skin response to testing with antigen was measured as an in vivo correlate of cell-mediated immunity. The delayed-type hypersensitivity responses to dinitrofluorobenzene, sheep red blood cells and D. immitis antigens were normal but the response to B. malayi antigens was significantly depressed, confirming that long-term B. malayi infection depresses cell-mediated immunity and that this depression is specific to B. malayi antigens.

Selective elimination of the delayed-type hypersensitivity response by extracorporeal thoracic duct filtration.

Calves were sensitized to tuberculin and histoplasmin. The delayed-type hypersensitivity skin response to these antigens was produced and the diameter of induration measured. Repeated skin tests prior to filtration demonstrated that the amount of induration produced by these skin tests was closely reproducible. Histoplasmin or tuberculin-coated columns were then introduced into a closed circuit extracorporeal thoracic duct circulation. A significant (P is less than 0.01) reduction or ablation of the delayed-type hypersensitivity response was obtained to the antigen used to coat the column. In contrast, no significant reduction occurred in the skin test response to the other antigen. Repeated skin tests to both antigens after the cessation of filtration showed a gradual rise toward prefiltration levels in the skin test to the filtered antigen. The results of these experiments indicate that a selective population of T lymphocytes can be removed from an in vivo system. The removal of these cells can selectively reduce a delayed-type hypersensitivity skin test response to a particular antigen. These results are consistent with the hypothesis that a type of in vivo selective immunosuppression can be produced by antigen-coated columns when they are placed in an extracorporeal thoracic duct lymph circulation system.