Lymphocyte activation. VIII. The application of a whole blood test to the quantitative analysis of PHA responsive T cells

Immunomodulatory Effects of Modified Bovine Colostrum, Whey, and Their Combination with Other Natural Products: Effects on Human Peripheral Blood Mononuclear Cells

Background

Many natural products have immunomodulatory properties. However, the mechanism of immunomodulatory activities are poorly understood.

Objectives

This study evaluated the influence of bovine colostrum products, a whey product, or their combinations with other natural products on human peripheral blood mononuclear cells' (PBMC) ability to produce cytokines upon activation.

Methods

PBMCs were pretreated with ultrafiltered colostrum, nano-filtered bovine colostrum, egg yolk extract, a botanical blend, colostrum + egg yolk extract, colostrum + egg yolk + botanical blend, and fermented whey and then stimulated with lipopolysaccharide or phytohemagglutinin. Cytokine production was measured by the Luminex assay.

Results

All study products demonstrated immunomodulatory properties by regulating cytokines production by activated PBMCs. Ultrafiltered colostrum alone displayed the highest immune stimulatory activity. It stimulated proinflammatory cytokine production by lipopolysaccharide-activated PBMCs and suppressed cytokine production by phytohemagglutinin-activated cells. Other study products mainly suppressed cytokine release by both cell types. The immunomodulatory properties depended upon the dose of the products used in the study.

Conclusions

All tested products modulated innate and adaptive immune cell activities. Most of the products demonstrated anti-inflammatory properties, except ultrafiltered colostrum, which stimulated the lipopolysaccharide-activated PBMC production of inflammatory cytokines. These products can be potentially used to support overall immune health.

Functional Evaluation of Proliferative T Cell Responses in Patients with Severe T Lymphopenia: Characterization of Optimal Culture Conditions and Standardized Activation Signals for a Simple Whole Blood Assay

In this methodological study, we describe an assay for analysis of proliferative T cell responses in patients with severe leukopenia. Severe treatment-induced cytopenia is observed in patients with malignant disorders who receive conventional intensive chemotherapy or autologous stem cell transplantation. The quantitative T cell defect can then be characterized by flow cytometric analysis of membrane molecule expression, whereas the functional status of the remaining T cell population is more difficult to evaluate. In the present study, we describe a standardized whole blood assay that requires small sample volumes and can be used for repeated analysis even in severely ill patients. The assay is based on the following strategy: (i) blood samples are diluted with the serum-free medium X-vivo 10, (ii) T cells are activated either with monoclonal immunoglobulin E (IgE) anti-CD3 or anti-CD3 plus anti-CD28; (iii) T cell proliferation is assayed by [(3)H]thymidine incorporation after 4 days of in vitro culture. These proliferative responses are not affected by the plasma levels of interleukin-2 (IL-2), sIL-2-R alpha, IL-7 and IL-15, and the kinetics of the response are not altered by the presence of exogenous cytokines. Detectable proliferation is observed for most patients with treatment-induced cytopenia. We conclude that the assay can be used for functional characterization of remaining T lymphocytes in patients with severe T lymphopenia.

Development and evaluation of a flow-cytometric assay of specific cell-mediated immune response in activated whole blood for the detection of cell-mediated immunity against varicella-zoster virus

A new assay for the detection of specific cell-mediated immune (CMI) responses is described. Whole blood, diluted 1/10 in medium, was cultured in the presence or the absence of specific antigens. Results were assessed by flow cytometric analysis with or without immunophenotyping to detect proliferating lymphoblasts among cultured cells. Interferon-gamma, IL-10, and IL-5 in culture supernatants are measured by ELISAs. The assay was evaluated using samples from 37 VZV-antibody-positive children with a history of chickenpox and samples from 15 seronegative children without a history of chickenpox; it displayed a sensitivity of 95% and a specificity of 100% for the detection of varicella-zoster virus (VZV)-specific CMI. The intraassay and interassay variations of the new test were lower than with the conventional assay for CMI, detecting thymidine incorporation in peripheral blood mononuclear cells (PBMCs). Cytokines were detected in only 70% of cultures from VZV-antibody-positive subjects. The cytokine response was restricted to IFN-gamma in most cases. The Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood (FASCIA) is a precise and accurate yet simple and convenient test that can be readily employed for the examination of single samples as well as for large-scale studies.

A new method for measuring lymphoproliferation at the single-cell level in whole blood cultures by flow cytometry

A simple and reproducible method is described for the measurement of proliferative responses to mitogens and antigens. Whole blood (WB) cultures are used and separation procedures are not necessary. Proliferative responses are monitored as development of lymphoblasts determined by flow cytometry (FC). Lymphocytes and lymphoblasts were shown to be exclusively selectable from mixed cell populations of WB by their light scatter profile on FC analysis. More than 90% of the lymphoblasts identified by FC were replicating DNA as determined by incorporation of the thymidine analogue 2-bromo-5-deoxyuridine. The WB/FC technique can be combined with triple immunofluorescence which was illustrated by determining subsets of lymphoblasts developing following stimulation with various mitogens and antigens. The new method was compared with the conventional method (peripheral blood mononuclear cell culture and proliferation measured by detection of DNA synthesis). The reproducibility of the methods were not different. The antigen-induced responses recorded by both methods correlated, but with significantly higher stimulation indices obtained by WB/FC. The latter procedure was also technically easier to perform and less time-consuming.

Whole blood culture for measuring mitogen induced T cell proliferation provides superior correlations with disease state and T cell phenotype in asymptomatic HIV-infected subjects

Proliferative responses to a panel of mitogens were compared in parallel for two sources of cells, whole blood (WB) and conventionally prepared peripheral blood mononuclear cells (PBMC), obtained from asymptomatic HIV seropositive and control subjects. Weak but statistically significant correlations of the proliferative responses were observed. Use of either lymphocyte source produced significant differences in the proliferative responses between the HIV seropositive and control subjects, but the use of WB was more powerful, with a smaller sample size being required to discriminate between the proliferative responses of the two study groups. Furthermore, proliferative responses using WB gave strong and highly significant correlations with a number of important changes in the surface marker phenotype of the lymphocyte populations in the HIV seropositive subjects including CD4, CD8, CD4:CD8 ratio and certain CD8 subsets, whereas strong correlations were not observed with the PBMC. The response of WB lymphocytes to staphylococcal enterotoxin B (SEB) was highly reproducible and provided the best discrimination between HIV-infected and control subjects. We conclude that the use of WB for measuring lymphoproliferation is easy, rapid, accurate, and discriminative for assessing and following the changes in immune function which occur in HIV seropositive subjects, applicable in the clinical as well as in the research setting.

Evaluation of a test system for measuring cytokine production in human whole blood cell cultures

A simple and reproducible method is described for the measurement of mitogen-induced cytokine production in cultures of both human peripheral blood mononuclear cells (PBMC) and whole blood. In the culture supernatants the cytokines interleukin-1 alpha (IL-1 alpha), interleukin-2 (IL-2), interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) were determined by a rapid and sensitive immunoassay using various monoclonal and polyclonal antibodies. Comparing the PBMC cultures with the whole blood system a good correlation was obtained if the cell number was taken into account. In the post-induction supernatants the cytokine values were found to follow typical kinetic curves. The protocol was evaluated by screening 60 cancer patients with primary disease and 60 healthy controls. A markedly reduced secretion of IFN-gamma and IL-1 alpha was found in the cancer patients compared to controls, although leukocyte and lymphocyte counts were almost identical in both groups.

Immunosuppression of lymphocyte blastogenesis in cattle infected with Ostertagia ostertagi and/or Trichostrongylus axei

Twenty 4-month-old calves were infected with O ostertagi and/or T axei and the responses to phytolectins were evaluated. Whole blood cultures were incubated with phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM). The blastogenic response was determined by tritiated thymidine uptake with results presented as counts per minute (cpm), stimulation indices (SI) and a mononuclear cell responsive index determined by dividing the phytomitogen induced cpm by the absolute mononuclear cell number per ul. The control group results were adjusted to 100 percent and changes in the percentage difference by the parasitized calves was determined. There was a decline in lymphocyte responsiveness to PHA beginning at the time of infection. Significant depression of responses to PHA was observed in all parasitized calves 8 weeks after infection although clinical signs of parasitism did not occur. Lymphocyte responses to PW, were not different in infected calves from the control, although the O ostertagi group had significantly higher PWM mean upon than the calves infected with T. axei. A slight depression in response to Con A was also observed at 8 weeks after infection followed by a significant increase after 10 weeks. The immunosuppression appeared to be a feature of gastrointestinal parasitism and related to infections with O. ostertagi and/or T. axei.

Abnormalities in intestinal mucosal T cells in homosexual populations including those with the lymphadenopathy syndrome and acquired immunodeficiency syndrome

Enteric infections are common in homosexual men. We have characterized the phenotypic distribution of small intestinal mononuclear cells among healthy homosexual men, homosexual men with lymphadenopathy syndrome, homosexual men with acquired immunodeficiency syndrome (AIDS), and a group of healthy heterosexual men. Total numbers of T lymphocytes in the small intestinal mucosa were significantly decreased in homosexual men with lymphadenopathy syndrome and AIDS. This decrease was most striking among the Leu-3a T-cell subset usually associated with helper/inducer function. The proportion of mucosal T cells reacting with Leu-2a (cytotoxic/suppressor phenotype) and lymphoid cells having the T305 antigen was significantly increased only in AIDS subjects. Both lymphadenopathy syndrome and AIDS subjects had a significant reversal of the normal mucosal helper/suppressor T-cell ratio. Mucosal helper/suppressor T-cell ratios and the distribution of mucosal mononuclear cells were normal in healthy homosexual men, although the same individuals had reversed helper/suppressor ratios among circulating T cells. Enteric infections in healthy homosexual men likely reflect sexual practices, and not a primary abnormality in intestinal mucosal immunity. In contrast, specific abnormalities in intestinal mucosal immunity may contribute to the persistent and opportunistic enteric infections that occur in AIDS.

Relationships between blood product exposure and immunological abnormalities in English haemophiliacs

Amongst 160 English haemophiliacs treated with clotting factor concentrates, abnormalities of T lymphocyte subset distribution (characterized by low T4/T8 ratios and high total T8 counts), low in vitro phytohaemagglutinin stimulation and raised serum IgG levels, were more common in patients with haemophilia A than B, in patients who had received heavier blood product exposure, and in adults rather than children. A slight reduction in lymphocyte and platelet counts was found in 26% and 17% of patients. In the sample of patients tested, serum alpha 1-thymosin levels were often raised, but beta 2-microglobulin levels were usually normal. Fractionation procedures used to prepare clotting factor concentrates, and the amounts of concentrate used, are more likely to be causally related to these immunological abnormalities than the origins of source donor plasmas.

The effects of intralipid and heparin on human monocyte and lymphocyte function

A group of patients were studied during the infusion of Intralipid as part of a parenteral nutrition regimen. Peripheral blood lymphocyte function was unaffected, but monocyte function (chemotaxis) was significantly depressed. A group of healthy volunteers received an intravenous bolus of 20% Intralipid. Blood was taken before and 15 min afterward for immunological studies, and the same changes were seen following Intralipid. Prior subcutaneous injection of 5000 U of heparin did not affect either immunological parameter, but completely prevented the changes in monocyte function caused by Intralipid. Electronmicrographs of monocytes from volunteers after injection of Intralipid, and autoradiographs of cells incubated with 14C-Intralipid in vitro, showed phagocytosis of fat particles by monocytes. These data suggest that Intralipid can have potentially serious side effects on the immune system, and that they may be alleviated by the use of subcutaneous heparin.

Normal lymphocyte responses to mitogens in term and premature neonates following normal and abnormal intrauterine growth

Cord blood lymphocyte responses to a panel of four mitogens were studied in 242 neonates using a whole blood technique. The patient population was divided into five gestational-age groups: 20-27.9, 28-32.9, 33-37.9, 38-41.9, and 42-44 weeks. Neonatal lymphocytes undergo a continuous reduction in proliferative responsiveness to the polyclonal ligands phytohemagglutinin (PHA) and concanavalin A (Con A) as gestation progresses from 20 to 44 weeks postconception. This is consistent with their change in unstimulated in vitro blastogenesis which when measured over the same developmental period is greatest in more immature neonates. Neonatal lymphocyte proliferative responsiveness to pokeweed mitogen (PWM) and staphylococcus protein A (SpA), however, was unrelated to gestational age. The influence of intrauterine nutritional deprivation on lymphocyte proliferative responses was studied in clinically uninfected newborns and compared to gestational age-matched controls with a normal nutritional status. Intrauterine nutritional deprivation was not associated with a decrease in mitogen-induced lymphocyte proliferation. Further, we explored the influence of several perinatal clinical settings commonly associated with fetal distress on cord blood lymphocyte responses to mitogens. Although perinatal stress in the form of low Apgar scores, meconium-stained amniotic fluid, and prolonged rupture of the amniotic membranes was not related to differences in mitogen induced lymphocyte proliferation, mode of delivery was. Cesarean section delivery as compared to vaginal delivery was associated with a significantly greater PHA-, Con A-, and SpA-induced neonatal lymphocyte response. Several alternative explanations for this finding are explored. Lastly, the purified protein thymosin fraction 5 was not associated with alteration in either neonatal or adult mitogen-induced lymphocyte proliferation.

Detection of impaired mitogen responses in autologous whole blood of cancer patients using an optimized method of lymphocyte stimulation

Mitogenic lymphocyte stimulation with six concentrations of phytohemagglutinin (PHA) was compared in 60 patients with advanced or metastatic cancer and 30 age- and sex-matched healthy controls using an optimized whole blood method. Since the method is simple and the number of technical variables relatively small, a "normal" range of PHA responsiveness expressed in absolute cpm, could be established. It is thus possible to directly compare results from different laboratories. A markedly reduced lymphocyte stimulation was found in cancer patients compared to controls, although leukocyte and lymphocyte counts were almost "normal". The implications of this finding are discussed with regard to immunosuppression by the tumor and previous chemotherapy.

Blastogenic response of lymphocytes derived from patients with hematopoietic malignancies to antigens of a type C retrovirus isolated from a Burkitt's lymphoma cell line

Cellular immune response to antigens associated with a type C retrovirus derived from Burkitt's lymphoma (BL) lymphoblastoid cells was studied in patients with hematopoietic malignancies, noncancer patients and healthy controls. Response was determined by lymphocyte blastogenesis assay measuring [3H]-thymidine incorporation, thereby enabling the calculation of stimulation indices (SI). Positive response (SI greater than 2.0) was demonstrated in patients with multiple myeloma (MM), chronic lymphocytic leukemia (CLL), chronic myelocytic leukemia (CML) and BL. No response was demonstrated in the non-cancer and healthy controls. Specific blastogenic response was obtained towards antigen extracted from three different cell lines infected with the tested type C retrovirus. No response was evident towards purified whole or purified disrupted virions or antigen extracted from murine myeloma MOPC-315 cells secreting a murine type C retrovirus or an antigen extracted from Mason-Pfizer monkey virus-infected NC-37 cells. The correlation between human hematopoietic malignancies and the in vitro lymphocyte blastogenic response to the BL-derived type C retrovirus was statistically highly significant.

A longitudinal study of leucocyte numbers and mitogenesis during the last ten weeks of human pregnancy

Leucocyte numbers rose consistently in normal primigravid women sampled repeatedly during the last ten weeks of pregnancy. The increase in total leucocyte count was significant from 35 weeks gestation to delivery and was directly related to an increase in neutrophils, while mononuclear cell numbers remained unaltered. In addition to the pregnancy associated neutrophilia there was a further increase in neutrophil counts at delivery. Using whole blood and purified leucocytes in culture, it was confirmed that pregnancy plasma contains suppressor factors which inhibit mitogenesis with PHA or Con A. There was no significant change in individual women's whole blood mitogenic response at any time during the sampling period except at delivery when there was a significant decrease. Culture of washed cells from pregnant women in non-pregnancy plasma restored their mitogenic response to levels found in non-pregnant control women, except at delivery when there was evidence of a cell-associated impairment of function. Purified leucocyte cultures from individual women sampled repeatedly from 30 weeks gestation to delivery gave variable responses although it was still possible to identify pregnancy-related plasma suppressor factors and delivery-associated impairment of leucocyte function in vitro.

Response of rhesus monkey lymphocytes to short-term administration of THC

Four Rhesus monkeys were subjected to daily administration of 2.5 mg of tetrahydrocannabinol (THC)/kg body wt, after establishing the norms for complete blood count, T- and B-cell concentrations, and the dose response of thymidine incorporation after PHA stimulation. THC was administered daily for 3 weeks, the treatment was stopped, and then the animals were allowed to recover for 4 weeks. Cellular responses, incorporation studies and fibrinogen levels were determined during the treatment and recovery phases. Compared to 4 vehicle-treated animals, the THC-treated animals experienced significant augmentation of both their total white cell and their neutrophil counts during the recovery phase which returned to normal levels during the recovery phase. There was no alteration in total lymphocyte count or T- or B-cell concentrations. Fibrinogen levels of the THC-treated animals during the treatment phase were also elevated compared to controls, and the levels diminished to the same values as the vehicle-treated animals during recovery phase. Possible mechanisms for the response of Rhesus monkeys to short-term administration of THC are discussed.

In vitro evaluation of porcine lymphocyte response to phytohaemagglutinin using a modified "whole blood" technique

The purpose of these investigations was to develop a modified whole blood technique for measuring quantitatively the responsiveness of pig peripheral blood lymphocytes to phytohemagglutinin (PHA) in vitro. Washed blood cells from a fixed volume of blood were suspended in culture medium supplemented with foetal calf serum and stimulated with a pure mitogenic PHA preparation. The stimulation was measured by the incorporation of 3H-thymidine. Data are presented to show the effect of different variables on the culture system. The transformation response was measured at different levels of PHA and the reproducibility of the different responses from repeated investigations was used to evaluate the usefulness of the test. The best reproducibilities of the stimulation response were found at the high PHA concentrations. Also the calculated PHA concentration giving maximum stimulation response had a relatively high reproducibility and indicates that this value is a convenient and reliable alternative measure of the functional capacity of the lymphocytes.

Genetic studies on the in vitro PHA-transformation of porcine blood lymphocytes

The response of pig peripheral blood lymphocytes to phytohaemagglutinin (PHA) was studied by a whole blood technique. The material for study comprised 441 offspring from one generation of a randomly mated Danish Landrace pig herd. The pigs were blood-sampled at a weight of 90 kg. After correlation for influence from other blood cells and for seasonal variation, the heritability of the PHA stimulation responses at different PHA concentrations were estimated. The heritability estimates ranged from 0.15 to 0.53. Also the PHA concentration giving maximum stimulation response, as calculated by a dose response function, was found to vary depending on genetic variation among the pigs with an estimated heritability of 0.38.

Reduction of non-specific radioactive counts in a whole blood microtiter plate assay of mitogenesis

Non-specific radioactive counts retained on the glass fiber filters from a multiple automatic sample harvester were reduced markedly by 3 simple changes in the procedure for harvesting thymidine-labeled whole blood cultured from microtiter plates. These modifications increased the sensitivity, precision and accuracy of the lymphocyte transformation assay.

Use of whole blood in the measurement of neutrophil migration

A whole-blood method was used for measuring neutrophil migration in micropore membrane. The method is reproducible (coefficient of variation (CV) 10.3% and 9.8% in two normal individuals tested repeatedly) and can be performed on an 0.25 ml lithium heparin blood sample. Migration is independent of leucocyte and erythrocyte counts and is comparable with that obtained for separated cells. As in separated cell techniques, cytochalasin and casein respectively inhibit and stimulate neutrophil migration. The technique is of value when testing large numbers of samples and when only small volumes of blood can be obtained, for example, in neonates.

Comparison of a simplified whole blood and isolated lymphocyte stimulation technique

Whole blood and isolated lymphocyte stimulation in healthy men were compared utilizing PHA, ConA, and PWM. Dose response curves with each of the 3 mitogens were found to differ with the two techniques of lymphocytes stimulation. When incubation time was lengthened PWM responses increased markedly in both the whole blood and isolated lymphocyte assays. Increased incubation time had no effect on PHA cultures and increased the responses with ConA in the whole blood method. In each study, responses with 3H-thymidine were comparable to responses utilizing 125IUdR.

The in vitro effect of levamisole on lymphocyte proliferation, polymorphonuclear leucocyte chemotaxis, basophil histamine release and platelet serotonin release in patients with atopic dermatitis

The in vitro effect of levamisole (LMS) on lymphocyte, neutrophil, basophil and platelet function was investigated in patients with severe atopic dermatitis and hyperimmunoglobulinaemia E. Lymphocyte stimulation by several concentrations of PHA, con A and PWM, polymorphonuclear leukocyte chemotaxis and basophil histamine release were unaffected by LMS (10 micrograms/ml). Platelet serotonin release induced by iodipamide was decreased in patient and control groups by LMS but release induced by methacholine, epinephrine and thrombin was not.

A rapid microtechnique for in vitro stimulation of canine lymphocytes using whole blood

A simple, rapid microtechnique utilizing whole blood has been developed for evaluating the in vitro stimulation of canine lymphocytes. The test uses 5 ul. of heparinized whole blood per culture in a microtiter plate and requires no serum supplement. Cultures are harvested by an automated multiple sample cell harvester. This technique permits large numbers of replicate samples to be tested on individual animals with minimal amounts of blood and minimal technician time.

The effect of levamisole on postoperative immunosuppression

Cell mediated immunity was studied before and after surgery in patients with colorectal cancer. Thymus-derived (T) lymphocytes were enumerated and their non-specific activity was measured by assessing phytohaemagglutinin (PHA)-induced blastogenesis. Specific T lymphocyte activity was measured by leucocyte migration inhibition in response to purified protein derivative of tuberculin (PPD) and autochthonous tumour extract. One group of patients received levamisole postoperatively and the other group consisted of controls. There was a more rapid return to preoperative levels of leucocyte migration inhibition to both antigens by the levamisole group. However, levamisole administration had only a marginal effect on the postoperative depression of cell counts and did not restore depressed lymphoblast transformation.

A micromethod for in vitro assay of lymphocyte proliferation in mouse whole blood

A microplate culture system to assay the in vitro proliferative responses of mouse peripheral blood lymphocytes to phytohaemagglutinin is described. The method utilises whole blood, a gamma-emitting isotopic label and semi-automated harvesting. Data are presented to show the effects of several variables on the culture system. The technique is suitable for serial study of the in vitro phytohaemagglutinin response in individual animals.

Lymphocyte multiplication in vitro induced by mitogens and antigens

A simple technique requiring only 0.2 ml whole blood for measuring the response of lymphocytes in cultures to each of various mitogens and antigens has been elaborated. The response is quantified by comparing the number of lymphocytes with and without a stimulating agent. The increment of cell numbers is given by a cell multiplication index. In healthy subjects PHA induced almost a doubling of the cell numbers in 3 days, i.e. an index of 1.90 +/- 0.38. After 7 days the indexes for PHA, PWM and Con A were 7.25 +/- 4.12, 2.72 +/- 0.65 and 1.81 +/- 0.31, respectively. PPD and Candida-extract induced cell multiplication in skin positive individuals, with indexes ranging from 1.12 to 3.05. In contrast, patients with various severe immune deficiencies showed decreased responses to at least one mitogen, depending on the type of the deficiency. Likewise, skin test negative individuals had no or faint in vitro response to the antigens. The method, which correlated well with the response by a conventional method for incorporation of tritiated thymidine, has a high degree of precision and sensitivity, and should be applicable for routine use.

Is dextran 70 a lymphocyte mitogen?

Dextran 70 ('Lomodex') roduced significant increases in thymidine incorporation in a modified whole-blood method of investigating lymphocyte blastogenesis. This blastogenesis occurred at molar concentrations of 7 X 10(-6) and 7 10(-5). At 7 X 10(-7) mol/l dextran alone did not significantly increase thymidine incorporation; however, when this concentration of dextran was added simultaneously with phytohaemagglutinin there was a significant increase in incorporation. Conversely when dextran was added before P.H.A., thymidine incorporation was decreased. These variable effects indicate that dextran 70 may be a B-cell mitogen. Dextran 70 is widely used and these effects on lymphocyte blastogenesis may be clinically relevant.