Construction of T cell hybridomas secreting allogeneic effect factor

BW5147 and Derivatives for the Study of T Cells and their Antigen Receptors

Like B cells, T cells can be immortalized through hybridization with lymphoma cells, a technique that has been particularly useful in the study of the T cell receptors (TCR) for antigen. In T cell hybridizations, the AKR mouse strain-derived thymus lymphoma BW5147 is by far the most popular fusion line. However, the full potential of this technology had to await inactivation of the productively rearranged TCR-α and -β genes in the lymphoma. BWα-β-, the TCR-gene deficient variant of the original lymphoma, which has become the fusion line of choice for αβ T cells, is now available with numerous modifications, enabling the investigation of many aspects of TCR-mediated responses and TCR-structure. Unexpectedly, inactivating BW's functional TCR-α gene also rendered the lymphoma more permissive for the expression of TCR-γδ, facilitating the study of γδ T cells, their TCRs, and their TCR-mediated reactivity.

A Chlamydia-Specific TCR-Transgenic Mouse Demonstrates Th1 Polyfunctionality with Enhanced Effector Function

Chlamydia is responsible for millions of new infections annually, and current efforts focus on understanding cellular immunity for targeted vaccine development. The Chlamydia-specific CD4 T cell response is characterized by the production of IFN-γ, and polyfunctional Th1 responses are associated with enhanced protection. A major limitation in studying these responses is the paucity of tools available for detection, quantification, and characterization of polyfunctional Ag-specific T cells. We addressed this problem by developing a TCR-transgenic (Tg) mouse with CD4 T cells that respond to a common Ag in Chlamydia muridarum and Chlamydia trachomatis Using an adoptive-transfer approach, we show that naive Tg CD4 T cells become activated, proliferate, migrate to the infected tissue, and acquire a polyfunctional Th1 phenotype in infected mice. Polyfunctional Tg Th1 effectors demonstrated enhanced IFN-γ production compared with polyclonal cells, protected immune-deficient mice against lethality, mediated bacterial clearance, and orchestrated an anamnestic response. Adoptive transfer of Chlamydia-specific CD4 TCR-Tg T cells with polyfunctional capacity offers a powerful approach for analysis of protective effector and memory responses against chlamydial infection and demonstrates that an effective monoclonal CD4 T cell response may successfully guide subunit vaccination strategies.

Gamma interferon interferes with the negative regulation of macrophage activation by prostaglandin E2

Activation of mouse macrophages for tumor cell killing is negatively regulated by prostaglandin E2 (PGE2). The effect of this hormone is to shut off cytolytic activity that is expressed as a consequence of activation. A lymphokine in the culture supernates of concanavalin A stimulated spleen cells has been shown to change the sensitivity of activated macrophages to the negative regulatory effects of PGE2, thereby maintaining activation, as manifested by the continued expression of tumor cell killing by these cells. Using a highly specific polyclonal antiserum and gamma interferon produced either by a T-cell hybridoma or by recombinant DNA technology we show here that one lymphokine responsible for mediating the maintenance effect is gamma interferon.

Macrophage activation: priming activity from a T-cell hybridoma is attributable to interferon-gamma

Antiviral and macrophage-priming activities in the supernatant medium of a subclone of a concanavalin A-stimulated mouse T-cell hybridoma were investigated. The two activities were associated with a molecular weight of approximately 50,000 and could not be separated by various approaches. Both activities were eliminated by a highly specific neutralizing antibody against mouse interferon-gamma, but not by antibody against interferon-alpha and -beta. The ratio of priming to antiviral activity in the hybridoma culture supernate was indistinguishable from the ratio obtained with mouse interferon-gamma prepared by recombinant DNA technology. It was concluded from these data that the priming activity in hybridoma culture supernates was attributable to interferon-gamma and that this mediator is one form of the lymphokine macrophage-activating factor. Interferon-gamma was greater than 800 times more efficient at priming mouse macrophages for tumor cell killing than was a mixture of interferon-alpha and -beta. This finding contributes to growing awareness that type II interferon may have greater immunoregulatory potential than type I interferons.

Identification of a T cell hybridoma that produces large quantities of macrophage-activating factor

A murine T cell hybridoma, constructed by fusion of alloantigen-activated T cells with the BW5147 T cell lymphoma, which produces a lymphokine capable of inducing tumoricidal activity in macrophages, has been identified. Lymphokine release could be detected only after mitogen stimulation of the T cell hybridoma culture. Upon cloning of the parental hybridoma, 24 out of 27 clones produced tumoricidal-inducing activity. Seven clones produced more cytocidal-inducing activity than did conventional supernatants, generated by concanavalin A stimulation of normal murine spleen cell cultures, which contained macrophage-activating factor (MAF). The supernatant of hybridoma clone 24/G1 was 25 times more active than conventional MAF preparations. Using supernatants from a variety of clones, the levels of macrophage-activating activity and interleukin 2 were found to vary independently of one another. The lymphokine produced by hybridoma clone 24/G1 appeared to be identical to conventional MAF by a variety of criteria including: (a) a requirement for a second signal for induction of tumoricidal activity in macrophages, (b) inactivation after incubation for 1 h at 65 degrees C, and (c) loss of activity after treatment at pH 4.0 but not at pH 5.0. Like conventional MAF, the hybridoma MAF eluted as a single peak after molecular sieve chromatography on Sephadex G100 and exhibited an apparent molecular weight of 55,000. Although somewhat heterogeneous, the majority of hybridoma 24/G1 MAF displayed an isoelectric point of 5.4 as determined using the chromatofocusing technique. These results thus illustrate the usefulness of T cell hybridomas in distinguishing between various lymphokine activities and indicate that the T cell hybridoma clone 24/G1 will be of particular usefulness in achieving the biochemical purification of substantial quantities of murine MAF.

Antigen-inducible, H-2-restricted, interleukin-2-producing T cell hybridomas. Lack of independent antigen and H-2 recognition

We developed a method for production of antigen-specific, H-2-restricted T cell hybrids. The tumor cell partner in the fusions was itself a T cell hybrid, FS6-14.13.AG2 (or its derivatives), which could be induced to produce the growth factor, interleukin-2 (IL-2), in response to a challenge with concanavalin A, but had no known antigen specificity. The normal T cell partner in the fusions was a population of lymph node T cell blasts that had been highly enriched in antigen-specific, H-2-restricted T cells by in vivo immunization, followed by in vitro challenge with antigen and clonal expansion in IL-2-containing medium. These fusions produced hybrids that grew constitutively in culture. A sizable proportion of the hybrids demonstrated the ability to produce IL-2 in response to a challenge with specific antigen presented by irradiated spleen cells of the appropriate H-2 type. Four cloned antigen/H-2-specific hybrid lines were produced. AO-40.10 responded to chicken ovalbumin (OVA) when presented by I-A(k)-bearing cells. DC1.18.3 responded to the apo form of beef cytochrome c when presented with I-A(d). AODK-10.4 responded to keyhole limpet hemocyanin (KLH) presented with I-A (d). AODK-1.16 also responded to KLH presented by a product of the I region of H-2(d), but the data were consistent with either a product of the I-J-I-E(d) region or a combinatorial molecule with elements from both I-A(d) and I-E(d)/I-C(d). Coincidentally, AO-40.10 was shown to have an unexpected alloreactivity with a product of H-2(b) mapping to the K-I-A region. These hybrids should prove invaluable as sources of monoclonal material for the study of the receptor(s) on T cells with H-2-restricted antigen specificities. We also generated T cell hybrids with two antigen/H-2 specificities by fusing an azaguanine-resistant clone of AO-40.10 to normal T cells with a different antigen/H-2 specificity. Many of the hybrids retained reactivity to OVA plus H-2(a) and to the second antigen/H-2 combination. None reacted to either OVA plus the second H-2 type or to the second antigen plus H-2(a). One of these hybrids was successfully cloned to produce the line AOFK- 11.11.1. It retained the ability to recognize OVA plus I-A(k) inherited from one parent, and KLH plus IA(f) inherited from the other. It did not recognize OVA plus IA(f) or KLH plus I-A(k). These results have some bearing on models describing the nature of T cell receptors for antigen recognized in association with H-2 products. They do not support models in which antigen and H-2 are recognized separately by two independent T cell receptors.