Cell-interaction molecules on immunocompetent lymphocytes. Development of anti-parent cell-interaction-molecule-receptor reactions in F1 hybrid mice and evidence for a unique F1 hybrid subset of interacting cells.

The experiments presented herein demonstrate that F1-parent T-B cell cooperation in vivo is significantly diminished by the addition of lymphoid cells of opposite parental type. This inhibition phenomenon is not a straightforward allosuppression mechanism as (a) it can be induced by parental lymphoid cells depleted by T cells, (b) it does not operate on cooperative interactions between homologous T and B cells of opposite parental type, and (c) absolutely requires the presence of F1 cells as participants in the reactions generated. The possible involvement of alloantibodies produced aberrantly under the experimental conditions employed has been ruled out by direct macrophage/antigen-presenting cell components of the reactions has been excluded. Because the presence of parental lymphoid cells only affects cooperative interactions between F1 T cells and B lymphocytes of opposite parental type but has no inhibitory effect on cooperative interactions between homologous F1, T and B cells, this (and other points discussed herein) strongly argues for the existence of one or more subsets of F1 interacting partner cells that are uniquely specific for F1, as distinct from either parental type cell interaction determinants. For reasons discussed, it appears that the most likely mechanism underlying such parental cell-induced inhibitory effects on F1-parent partner cell interactions is the development of anti-self cell interaction structure responses by F1 cells against the relevant self-specific cell-interaction structures of the parental partner cells involved.

Adaptive differentiation of murine lymphocytes. IV (Responder x nonresponder) F1 T cells can be taught to preferentially help nonresponder, rather than responder, B cells.

Responses to the synthetic terpolymer L-glutamic acid, L-lysine, L-tyrosine (GLT) in the mouse are controlled by H-2-1inked Ir-GLTgenes. (Responder x nonresponder) F(1) hybrid mice, themselves phenotypic responders, can be primed with GLT to develop specific helper cells capable of interacting with 2,4-dinitrophenyl hapten (DNP)-primed F(1) B cells in response to DNP-GLT. Unlike the indiscriminant ability of F(1) helper T cells for conventional antigens (i.e. not Ir gene-controlled), which can help B cells of either parental type (as well as F(1)) equally well, GLT-primed F(1) T cells can only provide help under normal circumstances for B lymphocytes of responder parent origin; they are unable to communicate effectively with nonresponder parental B cells (1, and the present studies). The present studies reveal, however, that the induction of a parental cell-induced allogeneic effect during priming of F(1) mice to GLT actually dictates the direction of cooperating preference that will be displayed by such F(1) helper cells for B cells of one parental type or the other. Thus, F(1) T cells, primed to GLT under the influence of an allogeneic effect induced by parental BALB/c cells, develop into effective helpers for nonresponder A/J B cells, but fail to develop effective helpers for responder BALB/c B cells, and vice-versa. In contrast, F(1) T cells, primed to GLT under the influence of an allogeneic effect induced by either parental type, display significantly enhanced levels of helper activity for B cells derived from F(1) donors. These results are interpreted to reflect the existence of two interdependent events provoked by the allogeneic effect: one event augments the differentiation of GLT-specific helper T cells belonging to the subset corresponding to the opposite parental type; this would explain the development of increased helper activity provided to partner B cells of opposite parental type (as well as of F(1) origin). The second event, we postulate, involves the production of responses against the receptors which normally self-recognize native cell interaction determinants; this form of anti-idiotype response is restricted against self- recognizing receptors of the same parental type used for induction of the allogeneic effect, hence explaining diminished helper activity of such F(1) cells for partner B lymphocytes of corresponding parental type.

Adaptive differentiation of murine lymphocytes. II. The thymic microenvironment does not restrict the cooperative partner cell preference of helper T cells differentiating in F1 leads to F1 thymic chimeras.

The cooperating preference of helper T cells originating from F1 bone marrow, but differentiating in adult thymectomized, lethally irradiated F1 recipients reconstituted with either f1 or homozygous parental thymus grafts was investigated. Cooperating preference was assayed by determining the levels of helper activity provided by antigen-primed T cells derived from such thymic chimeras for hapten-primed B lymphocytes obtained from conventional F1 or parental donors in adoptive secondary antibody responses in vivo. The results of these analyses revealed a tendency of helper T cells derived from parental thymic chimeras to provide better help for B cells of the same parental type corresponding to the origin of the thymus graft than for the opposite parent. Such preference was, however, only marginal and rarely were differences in levels of helper activity provided to the respective parental types statistically significant. Moreover, this marginal preference, when observed, pertained only to responses of the IgG class; no concordant preference in providing helper activity for IgE antibody responses was observed even with the same populations of thymic chimera helper T cells. Finally, in no instance was there any evidence of restriction in the classical sense of presence versus absence of help as we have routinely observed in all of our previous studies concerning genetic restrictions of T-B-cell cooperative interactions. Although the basis for differences in the studies reported here when compared to observations made in cytotoxic T-lymphocyte systems is unclear, and could reflect genuine mechanistic requirements concerning what directs H-2 restrictions in helper T cells and cytotoxic T lymphocytes, respectively, it is also possible that we are placing too much faith in our interpretations of data obtained in bone marrow chimera systems than is perhaps justified by the potentially great fragility of such systems.

Adaptive differentiation of murine lymphocytes. I. Both T and B lymphocytes differentiating in F1 transplanted to parental chimeras manifest preferential cooperative activity for partner lymphocytes derived from the same parental type corresponding to the chimeric host.

The concept of adaptive (selective) differentiation preducts that early differentiation of lymphocytes is conditioned by the environment in which such differentiation takes place. These processes appear to involve selection of lymphocytes according to their self-recognition between interacting lymphocytes is, at least in part, controlled by major histocompatibility complex-linked genes, then adaptive differentiation is also controlled by these genes. In these studies, we have tested the capacities of helper T lymphocytes and hapten-specific B lymphocytes primed in the environments of various combinations of bone marrow chimeras prepared between two parental strains (i.e. A/J and BALB/c) and their corresponding F1 hybrid (CAF1) to interact with primed B and T lymphocytes derived from conventional parent and F1 donors as well as all of the corresponding bone marrow chimera combinations. The results demonstrate clearly that (a) F1 transplanted to F1 chimeric lymphocytes display no restriction in terms of cooperative activity with all of the various partner cell combinations; (b) parent transplanted to F1 chimeric lymphocytes manifest effective cooperative activity only for partner cells from F) or parental donors corresponding to the haplotype of the original bone marrow donor, thereby behaving phenotypically just like conventional parental lymphocytes; and (c) F1 transplanted to parent chimeric lymphocytes display restricted haplotype preference in cooperating best with partner lymphocytes sharing the H-2 haplotype, either entirely or codomimantly, of the parental chimeric host. The implications of these findings for understanding certain controlling mechanisms for lymphocyte differentiation are discussed.

A rapid, semi-automated counting procedure for enumeration of antibody-forming cells in gel and nucleated cells in suspension.

A commercially available bacterial colony counter has been modified to permit rapid, highly accurate, semi-automated enumeration of antibody-producing plaque forming cells in semi-solid support medium as well as enumeration of nucleated cells in suspension on a standard hemacytometer chamber. This apparatus should therefore serve as an enormous time-conserving accessory to most modern laboratories involved in immunological research.

The anti-herpes simplex virus activity of n-docosanol includes inhibition of the viral entry process.

n-Docosanol-treated cells resist infection by a variety of lipid-enveloped viruses including the herpesviruses. Previous studies of the mechanism of action demonstrated that n-docosanol inhibits an event prior to the expression of intermediate early gene products but subsequent to HSV attachment. The studies reported here indicate that n-docosanol inhibits fusion of the HSV envelope with the plasma membrane. Evidence suggests that antiviral activity requires a time-dependent metabolic conversion of the compound. Cellular resistance to infection declines after removal of the drug with a t1/2 of approximately 3 h. Reduced expression of viral genes in n-docosanol-treated cells was confirmed by a 70% reduction in expression of a reporter gene regulated by a constitutive promoter inserted into the viral genome. Inhibited release in treated cells of virion-associated regulatory proteins--an immediate post entry event--was indicated by a 75% reduction in the expression of beta-galactosidase in target cells carrying a stably transfected lacZ gene under control of an HSV immediate--early promoter. Finally, the fusion-dependent dequenching of a lipophilic fluorescent probe, octadecyl rhodamine B chloride, inserted into the HSV envelope was significantly inhibited in treated cells. Inhibition of fusion between the plasma membrane and the HSV envelope, and the subsequent lack of replicative events, may be the predominant mechanism for the anti-HSV activity of n-docosanol.

The IgE antibody system: mature, peripheral B lymphocytes exert regulatory influences on the IgE systems of self-reconstituting, sublethally irradiated mice.

Previous studies have documented clear biological differences, such as sensitivity to moderate doses of irradiation, between B lymphocytes of the IgE type and B lymphocytes of other immunoglobulin isotypes. The present experiments were originally designed to explore such differences further by comparing the abilities of B lymphocytes derived from various IgE responder phenotypes, which differ among various inbred mouse strains, to reconstitute in a positive way the ability of sublethally irradiated recipient mice (of syngeneic or semisyngeneic type) to mount specific immune responses of the IgE antibody class. This was an important question with regard to delineating fully underlying differences in IgE responder phenotypes among different mouse strains, since heretofore most of the emphasis in experimentally defining such differences has focused on differences in T cell function, rather than B cell function. The experimental approach chosen to address this question seemed logical for two reasons: 1) it was our expectation that following exposure to the dose of irradiation employed (700 rads), individual mice would only slowly repopulate peripheral lymphoid tissues with their own stem cell products, and hence the expression of IgE responsiveness observed could be expected to reflect the responsiveness of the donor B cell population transferred into such recipients; and 2) since recipient mice were carrier-primed one week prior to irradiation in order to create a pool of radioresistant carrier-specific helper T cells, one could expect that this amplified pool of helper T cells would hasten the development of antibody production by the transferred donor B cells.

Purification of murine suppressive factor of allergy into distinct CD23-modulating and IgE-suppressive proteins.

The murine suppressive factor of allergy (SFA) has been purified from a T-cell hybridoma and found to consist of two functionally and biochemically distinct protein molecules. One protein (17 kDa) modulates the low-affinity Fc receptor for IgE on lymphocytes (i.e., CD23); it decreases the binding avidity of IgE to CD23-bearing B cells without affecting quantitative expression of CD23 and is thus designated epsilon-receptor-modulating protein. The second protein (30 kDa) suppresses IgE biosynthesis (i.e., SFA). This purified SFA suppresses interleukin 4-induced IgE and IgG1 synthesis by lipopolysaccharide-activated spleen cells but has no effect on other antibody isotypes; since the activity of SFA is not blocked by anti-interferon gamma monoclonal antibody, it is thus distinct from interferon gamma. The data presented indicate that epsilon-receptor-modulating protein and SFA are protein molecules that are involved in modulating the CD23 molecule and IgE antibody synthesis, respectively.

Anti-herpes simplex virus activity of n-docosanol correlates with intracellular metabolic conversion of the drug.

The 22-carbon fatty alcohol, n-docosanol, exhibits in vitro antiviral activity against several lipid-enveloped viruses including herpes simplex viruses 1 and 2 by a mechanism that interferes with normal viral entry into target cells. We previously reported that mammalian cells incorporate significant quantities of radiolabeled n-docosanol. Herein, we report that cells extensively metabolize the internalized fatty alcohol. This is evidenced by incorporation of up to 60% of cell-associated radiolabel into phospholipids that copurify with phosphatidylcholine and phosphatidylethanolamine. Analysis by chemical (Vitride) reduction suggests that a significant portion of n-docosanol is oxidized to n-docosanoic acid and then incorporated as an acyl group on polar lipids. A measurable amount of radiolabel, however, is resistant to Vitride reduction, consistent with incorporation of n-docosanol into ether lipids. The rate and extent of metabolic conversion of n-docosanol vary with the cell type and surfactant used to suspend the compound. Furthermore, the anti-HSV activity of n-docosanol is quantitatively proportional to the amount of metabolism observed. These findings suggest that the anti-HSV activity of n-docosanol involves cellular uptake and metabolism of the drug.

Regulation of IgE antibody production by serum molecules. IV. Complete Freund's adjuvant induces both enhancing and suppressive activities detectable in the serum of low and high responder mice.

Two biologically active serum molecules manifesting precisely opposite biologic effects, both of which are selective for IgE antibody synthesis, can be detected in the serum and ascites fluids of CFA-immune mice. One activity, described previously, is suppressive and hence termed suppressive factor of allergy (SFA); the other, reported for the first time herein, is enhancing and has been termed enhancing factor of allergy (EFA). The ability to detect one vs the other activity requires certain special manipulations such as different doses of low dose x-irradiation. Conclusive evidence for the existence of two distinct factors mediating these two opposing biologic effects was obtained in studies demonstrating that affinity chromatography on concanavalin A-Sepharose segregated the two molecular entities. Thus, SFA binds poorly or not at all to Con A-Sepharose, whereas EFA binds to Con A and can be recovered in the eluate eluted with the competitive sugar alpha-methyl-D-glucopyranoside.

Regulation of IgE antibody production by serum molecules. V. Evidence that coincidental sensitization and imbalance in the normal damping mechanism results in "allergic breakthrough".

Experiments presented in this paper were designed to test a new concept concerning the possible pathogenesis of the allergic phenotype. This concept, termed "allergic breakthrough" considers that one of the avenues toward the allergic phenotype involves coincidental sensitization combined with an imbalance in the normal damping mechanism that serves to limit IgE antibody production. The three predictions of this concept that can be tested experimentally are: 1) manipulations that are effective in heightening or re-establishing the damping mechanism should manifest persistence insofar as IgE antibody synthesis to the relevant allergen is concerned; 2) once allergic breakthrough has occurred, the height of production of IgE antibodies specific for the sensitizing agent should remain elevated at levels characteristic of the allergic phenotype, even after the threshold of damping activity has returned to a normal level; and 3) allergic breakthrough should display specificity in that breakthrough would occur in response to subsequent exposure to the specific antigen to which coincidental sensitization initially occurred, but not for other unrelated antigens. The studies presented herein confirm each one of these predictions, thereby providing substantial support for the validity of this concept as one possible distinguishing feature between individuals manifesting the nonallergic and allergic phenotypes, respectively.

Cell interactions between histoincompatible T an B lymphocytes. IX. The failure of histoincompatible cells is not due to suppression and cannot be circumvented by carrier-priming T cells with allogeneic macrophages.

Two possible explanations for the failure of primed histoincompatible T and B lymphocytes to cooperate in secondary responses of the IgG antibody class have been investigated in the present study: 1) The possible existence of subtle suppressive mechanisms developing as a consequence of mixing two histoincompatible cell populations; and 2) The possible inability of histoincompatible carrier-primed T cells to recognize and/or be induced to function by carrier determinants presented to them in association with foreign MHC antigens (i.e., the "altered-self" recognition hypothesis). Absence of suppression has been verified by two different approaches, including: 1) the failure of histoincompatible T cells, even in great excess, to interfere with physiologic cooperation between syngeneic T and B lymphocytes; and 2) the failure of histoincompatible B cells to interfere with physiologic cooperation between semi-syngeneic F1 hybrid T cells and parental B cells. The unlikelihood of the "altered-self" explanation for failure of histoincompatible T and B cells to cooperate has been incicated by an inability to circumvent the requirement for I-region identity by priming T cells with allogeneic macrophagebound antigen even when the latter cells are of identical haploytpe with the allogeneic B cells employed in the final cooperation assay. These results strongly substantiate the existence of true genetic restrictions in T-B cell intractions in secondary responses to hapten-protein conjugates. The validity of other observations indicating an absence of genetic restrictions in certain circumstances, considered in the context of our own data, has suggested the possibility that virgin T and B lymphocytes reciprocally influence one another during the course of cell interactions in response to antigenic and/or other signals, a process we term "adaptive differentiation."

Antiviral activity of 1-docosanol, an inhibitor of lipid-enveloped viruses including herpes simplex.

This article reports that 1-docosanol, a 22-carbon-long saturated alcohol, exerts a substantial inhibitory effect on replication of certain viruses (e.g., herpes simplex virus and respiratory syncytial virus) within primary target cells in vitro. To study the basis for its viral inhibitory activity, a suspension of 1-docosanol was formulated in an inert and nontoxic surfactant, Pluronic F-68; this suspension exerted potent inhibitory activity on the ability of susceptible viruses to infect cultured target cells. Susceptible viruses included wild-type herpes simplex viruses 1 and 2 as well as acyclovir-resistant herpes simplex virus 2 and also respiratory syncytial virus--all of which are lipid-enveloped. In contrast, nonenveloped poliovirus was not susceptible to the inhibitory action of 1-docosanol. Although the precise mechanism has yet to be defined, current evidence suggests that 1-docosanol inhibits viral replication by interfering with the early intracellular events surrounding viral entry into target cells. It is possible that interaction between the highly lipophilic compound and components of target cell membranes renders such target cells less susceptible to viral fusion and/or entry. If this mechanism proves to be correct, 1-docosanol may provide a broad spectrum activity against many different viruses, especially those with lipid-containing envelopes.

Immunologic tolerance to allergenic protein determinants: properties of tolerance induced in mice treated with conjugates of protein and a synthetic copolymer of D-glutamic acid and D-lysine (D-GL).

Conjugates of proteins and the synthetic copolymer of D-glutamic acid and D-lysine (protein-D-GL) reproducibly induce significant unresponsiveness to the protein antigens in experimental mice. Proteins studied include ovalbumin and antigen E of ragweed extract, the major allergen of ragweed pollen. The unresponsive state 1) can be induced in both unsensitized and previously sensitized experimental animals, 2) is selectively confined to responses of the IgE antibody class, 3) is long lasting, and 4) is highly antigen specific. IgE antibody responses can also be suppressed by administering comparable doses of unconjugated protein alone; however, the unresponsive state induced in this manner is only transient and rebound production of IgE antibody is often observed. Results from the studies of the cellular basis of the protein-D-GL induced unresponsiveness demonstrate that 1) protein-D-GL conjugates do not induce unresponsiveness at the level of protein-specific B cells, 2) tolerance is not induced by virtue of a detectable antigen-specific suppressor T cell mechanism, 3) tolerance is most probably induced in the antigen-specific helper T cell populations. The significant IgE-selective and antigen-specific tolerogenic activity of protein-D-GL conjugates make these compounds potential candidates for use as therapeutic agents in the treatment of IgE-mediated human allergic disorders induced by protein allergens.

Topical application of docosanol- or stearic acid-containing creams reduces severity of phenol burn wounds in mice.

Because of their reported antiviral and anti-inflammatory activities, cream formulations containing n-docosanol (docosanol) or stearic acid were tested for effects on chemically-induced burns in mice. In this model, injury was induced by painting the abdomens of mice with a chloroform solution of phenol. This was followed by the topical application of test substances 0.5, 3, and 6 h later. Progression of the wounds was assessed by a single evaluator after 8 h, using a numerical score of gross morphology. Docosanol- and stearic acid-containing creams substantially and reproducibly lessened the severity and progression of skin lesions compared to untreated sites with a 76% and 57% reduction in mean lesion scores, respectively. Untreated wounds appeared red and ulcerated; docosanol cream-treated wounds showed only slight erythema.

Biologically active molecules regulating the IgE antibody system: biochemical and biological comparisons of suppressive factor of allergy (SFA) and enhancing factor of allergy (EFA).

Studies in recent years directed at unraveling the complex regulatory mechanisms controlling IgE antibody production have demonstrated the existence of soluble factors that exert selective regulatory effects on the IgE antibody system. In addition, the demonstration of IgE-specific Fc receptors (FcR epsilon) on B and T lymphocytes, especially after exposure to high concentrations of IgE either in vivo or in vitro, has provided increasingly strong indications of an important role for such cells in the overall control of the IgE system. In our own laboratory, we have been studying soluble regulatory factors known as suppressive factor of allergy (SFA) and enhancing factor of allergy (EFA), which were initially identified by their selective, and opposing, regulatory effects on in vivo IgE responses in inbred mice. More recently, in an in vitro system in which it is possible to induce the de novo expression of FcR epsilon on lymphocytes cultured in the presence of monoclonal IgE, we reported that concomitant exposure of such cultured cells to SFA selectively blocked the induction of FcR epsilon expression. In the present study, we have extended these investigations by making a direct comparison between certain biological properties and biochemical characteristics of SFA and EFA. We found that SFA and EFA can be distinguished biochemically on the basis of size, SFA falling in the range of 30,000 daltons or so, and EFA falling in the range of 15,000 daltons. In examining their biological properties, we unexpectedly found that although SFA-enriched and EFA-enriched fractions exert dramatically distinct biological effects on in vivo IgE antibody synthesis (as implied by their names), the two respective active fractions are totally indistinguishable in their inhibitory effects on IgE-mediated induction of FcR epsilon + lymphocytes in vitro when intact spleen cell populations are exposed to monoclonal IgE. That the active entities in SFA and EFA responsible for inhibition of FcR epsilon induction do not exhibit IgE-binding properties was shown by the fact that adsorption on IgE-coupled affinity columns had no appreciable effect on their inhibitory capacities. This distinguishes these molecules from the IgE-binding factors described by Ishizaka and colleagues. Moreover, as previously documented for SFA, we found that EFA neither possesses immunoglobulinlike determinants nor binds to other immunoglobulin class molecules. Finally, chromatographically fractionated EFA was shown to exert its enhancing activity on in vivo IgE antibody production across strain barriers, thereby ruling out any genetic restriction on its functional capacity. A similar absence of genetic