Biological Activities of Guinea Pig Mitogenic Factor from Immune Lymphocytes Stimulated with Antigen

Mitogenic factor was produced by sensitized guinea pig lymph node cells stimulated with a specific antigen. Both T lymphocytes and macrophages were required for the production of this factor. The culture supernatant of lymphocytes containing the mitogenic factor exhibited a strong helping effect on the proliferative response of T lymphocytes to phytohemagglutinin (PHA). Mitogenic factor and the factor with the helping activity coeluted in the molecular weight range of 25,000-35,000 daltons in gel filtration. Furthermore the fraction containing mitogenic factor was found to support the proliferation of lymphoblasts induced by PHA or antigen, suggesting that the mitogenic factor may be the guinea pig equivalent of T cell growth factor (TCGF) reported in the mouse, rat, and human. On the other hand, the T cell-activating monokine of the guinea pig, possessing the helping activity for the proliferative response of T lymphocytes to PHA, never exhibited TCGF-like activity.     

Purified Protoplasmic Peptides of Mycobacteria: In Vivo and In Vitro Comparison of the Species Specificity of Purified Protoplasmic Peptides and Purified Protein Derivatives of Mycobacterial Culture Filtrates

The specificity of purified protein derivatives (PPD) prepared from the culture filtrates of Mycobacterium tuberculosis (PPD), M. kansasii (PPD-Y), M. intracellulare (PPD-B), and M. scrofulaceum (PPD-G) were compared to comparable protoplasmic extracts (PPP) of the same organisms by gel diffusion and delayed hypersensitivity reactions in sensitized guinea pigs. PPD and, to a lesser degree, PPD-Y demonstrated specificities sufficient to enable identification of homologously sensitized guinea pigs in the above group of four mycobacteria. PPD-B and PPD-G did not always elicit the largest reaction in homologously sensitized animals. The PPP sensitins from M. tuberculosis and M. kansasii produced as good skin reactions at 24 and at 48 hr as did their PPD counterparts. The PPP from M. scrofulaceum and M. intracellulare were more specific and more reactive than corresponding PPD, regardless of the time of comparison. Although based on different immunological mechanisms, the specificity of these two groups of sensitins, as demonstrated by delayed hypersensitivity, correlated well with serological comparisons in the gel diffusion test. The low degree of specificity of PPD-B and PPD-G in contrast to that of corresponding PPP was reflected in the precipitin bands in agar gel.     

Role of mediators of cellular hypersensitivity in the stimulation of the antibody formation to unrelated antigen

The effect of a concurrent delayed hypersensitivity reaction on the antibody response to sheep red cells was assessed by a plaque assay. Guinea pigs with delayed hypersensitivity to tuberculin purified protein derivative (PPD) or egg albumin showed an increased antibody response to sheep red cells when the cells were injected intravenously at the same time as PPD or egg albumin. This effect was transferred to normal guinea pigs by serum from guinea pigs with delayed hypersensitivity to PPD or egg albumin taken 24 hr after injecting the corresponding antigen. Supernatants containing migratory inhibitory factor were prepared by incubating lymphocytes from sensitized rabbits with antigen. These supernatants were injected with sheep red cells and gave rise to an enhanced plaque response. Similar results were obtained with supernatants from normal rabbit thymus cells. The role of mediators of delayed hypersensitivity in enhancing antibody formation and in T cell/B cell cooperation is discussed.     

Regulatory mechanisms of cutaneous delayed-type hypersensitivity: I. Suppression of cutaneous delayed-type hypersensitivity by migration inhibitory factor

The macrophage migration inhibitory factor (MIF) fraction was prepared from the immunoadsorbent column by using anti-guinea pig MIF antiserum. Suppression of cutaneous delayedtype hypersensitivity was achieved by intraperitoneal injection of the MIF fraction into the animals bearing macrophage-rich peritoneal exudates. Skin reactions induced by phytohemagglutinin (PHA) were also suppressed in these animals. Reactivity to skin reactive factor (SRF) was suppressed in these animals as well. The sera obtained from these animals exhibited the inhibitory activity against production of lymphokines from sensitized lymphocytes.     

Retention of 14C-Labeled Tuberculin Purified Protein Derivative in the Skin of Sensitized and Nonsensitized Animals

Tuberculin purified protein derivative labeled with (14)C ([(14)C]PPD) with a biological potency equivalent to the International Standard for tuberculin PPD was used to study the retention of tuberculin PPD in the skin of sensitized and nonsensitized animals. We found that [(14)C]PPD was almost entirely cleared from the skin test site during the first 18 to 24 h after injection and that when approximately 5% of the initial concentration of [(14)C]PPD was present in the skin test site, the size of the tuberculin skin reaction in sensitized guinea pigs was at its maximum. Furthermore, the addition of 5 or 50 mug of Tween 80 per ml to a solution of PPD did not change either the rate of clearance of PPD from the skin test sites of sensitized guinea pigs or the size of the tuberculin skin reactions. There was no difference in the rate of clearance of [(14)C]PPD from the skin test sites between sensitized and nonsensitized guinea pigs and between guinea pigs of different age. However, there was a significant difference in the rate of clearance of [(14)C]PPD between the guinea pig and the mouse. Finally, the percentage of [(14)C]PPD retained in the site of injection at 24 h was in the neighborhood of 5% of the initial concentration of the solution of PPD injected. The significance of these phenomena is discussed.     

Antibodies to guinea pig lymphokines. II. Suppression of delayed hypersensitivity reactions by a "second generation" goat antibody against guinea pig lymphokines.

A "second generation" antibody to a highly purified lymphocyte product was raised in a goat against material eluted from a rabbit anti-guinea pig lymphokine immunoadsorbent column. This anti-lymphokine serum, in constrast to anti-lymphocyte serum (ALS) did not appear to contain cytotoxic antibodies directed against membrane antigens on guinea pig lymph node lymphocytes. Furthermore, the anti-lymphokine serum did not inhibit the formation of spontaneous T rosettes nor significantly depress lymphocyte response to mitogens. The anti-lymphokine serum totally suppressed the delayed skin reactivity to PPD and contact sensitivity to DNCB when injected intradermally around the site of antigen challenge. By contrast, intradermally injected ALS did not appear to suppress the PPD response in sensitized guinea pigs. Intravenously and i.p. administered anti-lymphokine serum was somewhat less effective in suppressing the delayed skin response to PPD. The intradermal injection of the antiserum had no effect on nonspecific inflammation evoked by turpentine-olive oil or on the extravasation of circulating Evans blue evoked by intradermally injected histamine. Histologic examination of 24-hr DNCB-induced skin lesions from sensitized guinea pigs treated with intradermally injected anti-lymphokine serum showed marked reduction of mononuclear infiltration of the dermis and of epidermal lesions, as compared with skin sites taken from sensitized animals pretreated with normal goat serum. The anti-lymphokine serum injected i.v. also markedly reduced the perivascular infiltration of the dermis and subcutis in skin reaction sites from sensitized animals challenged with PPD. Intravenous treatment with ALS for 3 consecutive days caused extensive depletion of the paracortical areas of peripheral lymph nodes whereas treatment with normal serum and anti-lymphokine serum caused no such depletion. It is proposed that the anti-lymphokine serum is directed against activated lymphocyte products, one of them being MIF. These products are involved in the mediation of delayed hypersensitivity reactions. This is in marked contrast to ALS, the suppressive action of which appears to be central rather than peripheral.     

Properties of TAS-1D3, a Tuberculin-Active Substance from BCG,in Regard to Delayed Hypersensitivity

The properties of TAS-1D3, a tuberculin-active substance purified from the cell extract of Mycobacterium bovis BCG, were studied in vivo and in vitro. In the delayed hypersensitivity skin reaction, TAS-1D3 showed far more potent activity than tuberculin purified protein derivative (PPD) in guinea pigs sensitized with BCG vaccine. This was consistently observed from 6 to 24 weeks after sensitization. The histological findings of the skin reaction to TAS-1D3 were similar to those of the reaction to PPD. Moreover, TAS-1D3 induced well both thymidine incorporation and the production of migration inhibitory factor (MIF) by the spleen cells from guinea pigs sensitized with BCG vaccine. In contrast, TAS-1D3 showed weaker activity than PPD in guinea pigs sensitized with either heat-killed M. tuberculosis Aoyama B or heat-killed M. tuberculosis H37Ra, and it weakly stimulated the spleen cells from animals sensitized with M. tuberculosis Aoyama B to incorporate thymidine and to produce MIF.     

Comparison in sensitized and unsensitized guinea-pigs of tuberculin PPDs RT 23 and PPD-M by skin tests and lymphocyte stimulation tests. Effect of immunization time

The biological activities of tuberculin PPD RT 23 and the International Standard for Purified Protein Derivative of Mammalian Tuberculin (PPD-M) were compared in sensitized and unsensitized guinea-pigs by skin tests and lymphocyte stimulation (LS) tests. Estimates of relative potency (RP) from skin test results were dependent on the dose level, on the immunogen used, and, in guinea-pigs immunized with killed tubercle bacilli in oil, also on the immunization time. Relative potency estimates from LS results were dependent on the source of the lymphocytes and were different from estimates obtained from skin tests. Lymphocyte stimulation dose-response curves for the tuberculins were qualitatively different. In contrast to RT 23, PPD-M gave rise to non-specific skin reaction in unsensitized guinea-pigs. Both tuberculins were mitogenic to lymph node lymphocytes isolated from unsensitized guinea-pigs, PPD-M being the more mitogenic of the two tuberculins. The present results confirm that qualitatively different tuberculins cannot be unambiguously calibrated in identical terms and thus emphasize that the uncritical use of (international) standards should be avoided in tuberculin calibration.     

Isolation and partial characterization of immunologically reactive fractions from chitinase digested cell wall of Trichophyton mentagrophytes

Summary Cell wall preparations ofTrichophyton mentagrophytes were digested with chitinase following which various fractions were isolated by ultrafiltration and Sephadex gel filtration. All fractions isolated contained both polysaccharide and peptide material. A correlation was seen between those fractions capable of eliciting immediate and delayed skin reactions in sensitized guinea pigs and those capable of stimulating thein vitro proliferation of lymphocytes taken from sensitized guinea pigs. These immunologically active fractions also developed precipitin lines with antiserum taken from sensitized animals. A low molecular weight fraction was found to be completely reactive immunologically (UM_2(a)), and appeared to have a molecular weight in the range of 2,000–4,000 as assessed by ultrafiltration and gel filtration studies.This work was supported by grant number 3411 from the Medical Research Council of Canada.A. Kh. Al-Rammahy was supported by a scholarship from the Ministry of High Education, Iraq.     

Chromatographic analysis and immunobiologic properties of tuberculins]

Immunobiologic activities of tuberculin preparations and their components have been comparatively studied using gel filtration and high-performance liquid chromatography (HPLC) techniques. It is shown that high-molecular weight fraction of protein-purified derivate tuberculin (PPD) had higher activity as compared to nonfractionated preparation in skin tests on guinea pigs sensitized with Mycobacterium bovis BCG as well as in enzyme-linked immunosorbent assay with affinity purified rabbit antibodies against PPD. Using the preparative HPLC-technique we failed to isolate a component of PPD having greater tuberculin test potency than nonfractionated preparation.     

Trace elements incorporated into the culture medium of Mycobacterium tuberculosis promote the presence of tuberculoprotein C in the preparation of purified protein derivatives

Two purified protein derivatives (PPDs) were prepared from Mycobacterium tuberculosis, H37Ra. One of the PPDs was prepared from the culture filtrate of organisms grown on Proskauer-Beck medium to which trace elements had been added. The other PPD was prepared from the culture filtrate of organisms grown on the same medium but without trace elements, and was used as the control. Comparative skin reactions in sensitized rabbits showed that the PPD prepared from organisms grown in the presence of trace elements was less potent than the control. Since it has long been recognized that of the many tuberculoproteins present in PPD, the C protein (a 44 to 66 kDa protein) was always the least potent fraction when tested in equivalent concentrations in both serological and skin test assays, the possibility existed that the PPD obtained from organisms grown in trace element medium had more of the C protein complex than the control. Comparative studies of these two PPDs in terms of their chemical composition, skin test responses, and electrophoretic profiles obtained by SDS-polyacrylamide gel electrophoresis provide support for this assumption.     

Isolation of tuberculin peptides from tuberculin purified protein derivative (PPD).

Tuberculin purified protein derivative (PPD) obtained from the filtrate of Mycobacterium tuberculosis was hydrolysed with proteinase, trypsin, or chymotrypsin. Each hydrolysate consisted of a tuberculin peptides mixture (TPM). From each TPM 16 fractions were obtained by ion-exchange chromatography on Dowex 50W-X8 but only one fraction was isolated from each of the 16 fractions which showed tuberculin activity in guinea pigs sensitized with M. bovis (bcg) or M. tuberculosis. This fraction was designated "purified tuberculin peptide" (PTP). The PTP fraction from the proteinase hydrolysate (PTP-proteinase) was rechromatographed on Dowex 1-X2 and two tuberculin peptide fractions having molecular weights of 3200 and 12,000 were isolated. The potency of these two fractions was assessed in guinea pigs sensitized with M. bovis (BCG) and with M. tuberculosis and they were approximately 4 to 7 times more potent than either the international standaCG and of at least equal potency to either PPD-S or Connaught PPD in guinea pigs sensitized with either M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium whereas very little if any cross-reactivity was elicited by these two fractions. This lack of response indicates that either fraction could be used as an aid to differentiate between sensitization due to M. tuberculosis or M. bovis and sensitization attributed to other mycobacteria.     

In vitro studies on transplantation immunity. I. MIF production by sensitive lymphocytes in mice

Sensitized lymphocytes from mice immunized with skin homografts produce migration inhibitory factor upon incubation with lymphocytes (antigen) from the sensitizing strain. The MIF is produced within 14 hr following incubation of sensitized lymphocytes and antigen. In this reaction, antigenic specificity is a prerequisite for MIF production; however, the action of MIF transcends the strain barrier. Also, MIF produced in homograft reactions in mice inhibited the migration of peritoneal cells from normal guinea pigs. Finally, lymphocytes from mice bearing skin homografts do not develop the capacity to produce MIF prior to the rejection of the sensitizing skin grafts.     

Interspecies transfer by "immune" RNA of lymphocyte proliferative response to specific antigen

Ribonucleic acid (RNA) extracted from the lymph nodes of BCG sensitized cattle transferred tuberculin sensitivity to normal guinea pig lymphocytes as indicated by increased incorporation in vitro of ³H-thymidine in response to Purified Protein Derivative (PPD). The RNA treated lymphocytes were unresponsive to a nonspecific antigen, histoplasmin. Ribonuclease treatment of the RNA abolished its ability to transfer tuberculin reactivity and RNA extracted from the lymph nodes of normal cattle was also ineffective.     

Functional activation of immune lymphocytes by antigenic stimulation in cell-mediated immunity. III. A soluble factor released from LPS-stimulated peritoneal adherent cells effective in antigenic activation of sensitized lymphocytes.

Antigen-induced production of migration inhibitory factor (MIF) by sensitized lymphocytes requires macrophages to effectively stimulate lymphocytes with soluble antigen in vitro. The present study showed that macrophage-depleted lymphocytes of sensitized guinea pigs could be activated with antigens when the culture supernatant of peritoneal adherent cells pulse-stimulated with a macromolecular fraction of bacterial lipopolysaccharide (LPS) was added to the lymphocyte culture. The apparent macrophage-replacing activity was found in the fraction which emerged slightly ahead of serum albumin upon gel filtration of the culture supernatant, and the activity was shown to be destroyed by heating at 65 °C for 30 min or by trypsin digestion. These results appeared to show that the activity was due to a protein component, most probably released from macrophages. Two-step culture experiments revealed that the soluble factor should be present in the early stage of the culture to activate the macrophage-depleted immune lymphocytes with antigen, as well as in the later stage when the presence of antigen in the medium is no longer required. Furthermore, the factor was shown to act in the activation of a T-cell-enriched fraction of immune lymphocytes. The factor appeared to be playing some essential role in making an antigenic stimulus effective for the activation of immune lymphocytes.     

Partial purification, physicochemical characterization and biological function of a rosette-decreasing factor (RDF) extracted from guinea pig thymus.

A factor that decreases rosette formation between guinea pig T-cells and rabbit red blood cells (RRBC) was extracted from the thymus of the guinea pig. The active factor could be extracted from the spleen as well as the thymus, but not from the liver or kidney. The active factor of the thymic extract was found in the precipitates produced by 80% saturated ammonium sulfate and it was separated from the water-soluble fraction of the precipitates. The molecular weight of the partially purified substance was estimated to range between 10,000 and 30,000 by filtration through a diaflow membrane. From the studies on physicochemical characterization, it might be a heat-resistant basic peptide probably bound to a ribonucleotide moiety. This factor reduced rosette formation between RRBC and guinea pig T-cells, but did not reduce erythrocyte-antibody-complement rosette formation. This factor also inhibited mitogen (concanavalin A, phytohemagglutinin-P)- induced DNA synthesis of guinea pig lymphocytes and antigen-induced DNA synthesis of sensitized guinea pig lymphocytes.     

Tuberculin-sensitized lymphocytes detected by altered electrophorectic mobility distributions after incubation with the antigen PPD.

Lymphocytes from donors who had had tuberculosis (a disease known to provoke a cell-mediated immunity) were incubated with the tuberculin antigen, purified protein derivative (PPD), and their distribution of electrophoretic mobility was determined by laser Doppler spectroscopy. In 75% of the cases, the distribution showed a new, high mobility cell subpopulation that was not present before exposure to the PPD. Control lymphocytes from individuals with negative skin tests or no record of tuberculosis showed no mobility changes after incubation with PPD. These observations indicate that the new mobility subpopulation arose from a specific interaction between the antigen and sensitized cells of the donors.     

Tuberculin response of lymphocytes from human skin test nonreactors; evidence for in vitro primary sensitization of T lymphocytes.

Tuberculin-purified protein derivative (PPD) is a B-lymphocyte mitogen in a variety of experimental animals. Although peripheral blood mononuclear cells (PB MNC) from healthy human tuberculin responders consistently responded to PPD by increased incorporation of [³H]thymidine, cell fractionation studies showed this to be due to T-lymphocyte rather than B-cell blastogenesis. Moreover, utilizing thymidine suicide experiments, the T-lymphocyte response could be categorized as antigenic rather than nonspecific mitogenic reactivity. Kinetic studies revealed a delayed peak of PPD-induced thymidine incorporation in PB MNC from tuberculin skin test-negative as compared to skin test-positive donors. This suggested in vitro primary sensitization of T lymphocytes to PPD, which was corroborated in experiments demonstrating tuberculin reactivity of human umbilical-cord blood lymphocytes.     

Stimulation of human B lymphocytes by Nocardia-delipidated cell mitogen and derived fractions from N. opaca. Structure-activity relationship

Nocardia-delipidated cell mitogen (NDCM), a particulate fraction prepared from Nocardia opaca, is able to stimulate the proliferation of small resting human B lymphocytes and their differentiation into Ig-secreting cells. This fraction contains two active structures: the cell wall peptidoglycan (PG) and a fraction (Cy I) derived from the cytoplasmic compartment. Treatment of insoluble PG with various bacteriolytic enzymes showed that the minimal structure required for mitogenic activity is more complex than that required for the differentiation of human lymphocytes. The mitogenic activity of cell wall fractions varies in different bacterial species; that prepared from N. opaca is the more potent. Both mitogenic structures of N. opaca induce higher responses in infant and adult PBL as compared to cord lymphocytes. The differentiation of B lymphocytes into Ig-secreting cells induced by PG fractions is T-dependent.     

Comparative Study of 14C-Labeled Purified Protein Derivative from Various Mycobacteria: II. Skin Cross-Reactivity in Sensitized Guinea Pigs

A study on skin cross-reactivity between stabilized ¹⁴C-labeled mycobacterial antigens, namely tuberculin purified protein derivative (PPD; from Mycobacterium tuberculosis), PPD-A (M. avium), PPD-Y (M. kansasii), PPD-G (M. scrofulaceum), PPD-B (M. intracellulare), and PPD-F (M. fortuitum), has been carried out in groups of guinea pigs sensitized with one of the following heat-killed mycobacteria: M. tuberculosis, M. avium, M. kansasii, M. scrofulaceum, M. intracellulare, or M. fortuitum. For each type of sensitization, the average response for the corresponding PPD antigen was higher than the average response for any of the other antigens. However, the responses to the heterologous PPD antigens were not necessarily significantly different among themselves, and the significant differences of the heterologous PPD antigens were distributed differently according to the type of sensitization. Therefore, ¹⁴C-PPD antigens skin cross-reacted in guinea pigs essentially in the same manner as reported by others for nonradioactive PPD antigens.