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Thymosin fraction 5 restored the capacity of peripheral blood lymphocytes (PBL) from thymectomized adult guinea pigs sensitized with purified protein derivative (PPD) to produce migration inhibition factor (MIF) as measured in an agarose droplet microassay with peritoneal exudate cells. PBL from sham-thymectomized and normal PPD-sensitized guinea pigs did not lose their capacity to make MIF in response to PPD and were unaffected by thymosin polypeptides. Splenic and lymph node lymphocytes of thymectomized guinea pigs retained their antigen responsivity , suggesting that thymectomy did not affect fully matured, localized memory cells, but caused an accumulation in the circulation of partially matured, antigen-sensitive lymphocytes that could release MIF only in the presence of thymic factors. Various thymosin polypeptides were tested in this system and only thymosin alpha 1, an acidic polypeptide of 28 amino acid residues, showed consistent activity. This polypeptide, which has a molecular weight of 3,108, did not inhibit macrophage migration by itself, but 10-1,000 ng/ml was able to completely restore the MIF-producing capability of PBL from thymectomized guinea pigs. A standardized method for pooling and cryopreserving guinea pig PBL was developed, allowing multiple assays to be performed with a single pool of cells. The specificity of this bioassay system has made it a useful tool in evaluating the thymosin alpha 1 activity present in various thymosin preparations, and in validating biological activity of thymosin alpha 1 preparations made by synthetic or recombinant DNA techniques.

Previous studies with neutrophils from newborn infants compared to neutrophils from healthy adults have documented increased respiratory burst activity including enhanced superoxide anion (O2-) production, nitroblue tetrazolium dye reduction, and hexose monophosphate shunt activity. To investigate the biochemical basis for these observations, we examined oxidative metabolism in membrane-rich fractions of neutrophils. Neutrophils from cord blood of vaginally delivered term infants or healthy adults were disrupted by nitrogen cavitation and subcellular fractions collected on discontinuous sucrose density gradients. Subcellular fractions of newborn neutrophils separated in a fashion identical with samples from healthy adults. Activity of alkaline phosphatase, a plasma membrane marker, was increased 4- to 5-fold in disrupted cells free from nuclei (postnuclear supernatant) as well as plasma membrane fractions from newborn samples compared to those from healthy adults. Content of lactoferrin, a specific granule marker, was decreased in postnuclear supernatants but equivalent in specific granule fractions of newborn cells compared to those from adults. No differences were noted in myeloperoxidase content of postnuclear supernatants or any other subcellular fraction. Plasma membrane fractions from phorbol myristate acetate-stimulated cord blood neutrophils made significantly more O2- than samples from adults (newborn 32.9 +/- 8.1 nmol O2-/min/mg protein mean +/- SEM, n = 3 versus adult 10.8 +/- 4.2, n = 3; p less than 0.05). Plasma membrane-rich fractions were also collected by the technique of differential centrifugation and kinetic parameters of the NADPH-dependent oxidase enzyme(s) were measured for vaginally delivered newborn and adult samples.(ABSTRACT TRUNCATED AT 250 WORDS)

In an effort to make interleukin-2/lymphokine-activated killer cell (IL-2/LAK) therapy safer for cancer patients, we examined the efficacy of using Fenwal PL732 bags as tissue culture flasks. These bags can be sterilly connected using tubing kits thus reducing the risk of contamination to the cells. Peripheral blood mononuclear cells were obtained from normal donors or cancer patients undergoing IL-2/LAK cell therapy. Following Ficoll-Hypaque purification, these cells were incubated in the presence of IL-2 in either PL732 plastic bags or standard tissue culture flasks. Our results showed that LAK cells could be generated from either normal donors or cancer patients in the bags as well as in the flasks. Comparisons were made of the LAK cell populations obtained from the two sources and showed that each was similar in terms of morphology as determined by Wright stain differentials. The populations of cells were also similar in regard to cell surface phenotype as determined by flow cytometric analysis. In addition, recoveries from either tissue culture vessel as well as cell viability of the LAK cells were comparable. Finally, the LAK cells obtained from both sources were assessed for cytolytic activity against the tumor cell lines K562 and Daudi. These results showed that the cytolytic activity of the LAK cells against these target cells was the same whether the cells were obtained from the flasks or the bags.

Tranquilization using 3 mg/kg of ketamine by intramuscular injection followed by inhalation anaesthesia using halothane was performed on an adult Cape fur seal in order to perform a metatarsal amputation and ophthalmic examination. Ketamine was found to have little effect at the dosage used while halothane proved to be a rapid induction agent providing a safe, continued level of surgical anaesthesia. Variations in cardiac rate and body temperature were recorded during anesthasia and blood was sampled for haematology.

A partially purified extract from thymus tissue termed thymosin Fraction 5 has been shown to reconstitute immunological deficiencies resulting from the lack of thymic function in several animal models, as well as humans with primary and secondary immunodeficiency diseases. Thymosin Fraction 5 consists of a family of polypeptides with molecular weights ranging from 1,000 to 15,000. Several of these polypeptides contribute individually to the biological activity of the parent compound. Two polypeptide components of thymosin Fraction 5, termed thymosin alpha1 and polypeptide beta1, have been characterized chemically and biologically. Thymosin alpha1 is a highly acidic molecule composed of 28 amino acid residues. This polypeptide has potent biological activity and has been found to be 10 to 1,000 times as active as thymosin Fraction 5 in one in vivo and several in vitro bioassay systems designed to measure differentiation and function of thymus-dependent lymphocytes (T cells). Polypeptide beta1, in contrast, is inactive in our bioassay systems, suggesting that it is not involved in thymic hormone action. Sequence analysis and homology studies have indicated that polypeptide beta1, although present in Fraction 5, does not contribute to the biological activity of thymosin Fraction 5.

Thymosin fraction 5 contains several distinct hormonal-like factors which are effective in partially or fully inducing and maintaining immune function. Several of the peptide components of fraction 5 have been purified, sequenced and studied in assay systems designed to measure T-cell differentiation and function. These studied indicate that a number of the purified peptides act on different subpopulations of T-cells (see Figure 1). Thymosin beta 3 and beta 4 peptides act on terminal deoxynucleotidyl transferase (TdT) negative precursor T-cells to induce TdT positive cells. Thymosin alpha 1 induces the formation of functional helper cells and conversion of Lyt- cells to Lyt 1+, 2+, 3+ cells. Thymosin alpha 7 induces the formation of functional suppressor T-cells and also converts Lyt- cells to Lyt 1+, 2+, 3+ cells. These studies have provided further evidence that the thymus secretes a family of distinct peptides which act at various sites of the maturation sequence of T-cells to induce and maintain immune function. Phase I and Phase II clinical studied with thymosin in the treatment of primary immunodeficiency diseases, autoimmune diseases, and cancer point to a major role of the endocrine thymus in the maintenance of immune balance and in the treatment of diseases characterized by thymic malfunction. It is becoming increasingly clear that immunological maturation is a process involving a complex number of steps and that a single factor initiating a single cellular event might not be reflected in any meaningful immune reconstitution unless it is the only peptide lacking. Given the complexity of the maturation sequence of T-cells and the increasing numbers of T-cell subpopulations that are being identified, it would be surprising if a single thymic factor could control all of the steps and populations involved. Rather, it would appear that the control of T-cell maturation and function involves a complex number of thymic-specific factors and other molecules that rigidly control the intermediary steps in the differentiation process.

We obtained tumor specimens from patients with cancer in an effort to activate and expand the tumor-infiltrating lymphocytes for therapeutic use. With the use of finely minced tumor preparations from eight different tumor types, recombinant interleukin-2, and lymphokine-activated killer cell-conditioned medium, lymphocytes were expanded in vitro. After 4 weeks, the tumor cells were virtually absent from the cultures. At this point, the lymphocytes were termed "tumor-derived activated cells" (TDACs). Over 90% of the TDACs from each of the different tumor types were T lymphocytes, and the percentage of cells expressing either CD4 or CD8 varied considerably from population to population. The lymphocytes showed specific cytolytic activity in melanoma and colon and renal cell carcinomas. Continued expansion and long-term growth of the TDACs, as well as maintenance of the cytolytic activity, were achieved by periodic stimulation of the TDACs with irradiated autologous tumor cells. In a clinical study of 28 patients with cancer, we generated a mean number of 1.2 X 10(11) TDACs in an average time in culture of 69 days. These TDACs were subsequently infused into the patients with cancer. TDACs appear to represent an important resource for biotherapy of patients with cancer.

Doxorubicin (DXR) conjugated to murine monoclonal antibodies (MoAb) raised against human breast tumor cells demonstrated a MoAb-specific, molar ratio-dependent in vitro cytotoxicity. These conjugates were prepared on a scale sufficient to allow for subsequent clinical trials (1 to 3 g of MoAb per conjugation reaction). The conjugation reaction proceeded via an N-hydroxysuccinimide (NHS) active ester intermediate of cis-aconityl-DXR (CA-DXR), resulting in a cis-aconitate acid-sensitive linker between the DXR and MoAb. Molar ratios of DXR to MoAb ranged from 40 to 45. The immunoreactivity of conjugated MoAb was only slightly decreased from naked MoAb. When immunoconjugates were incubated with MoAb-reactive tumor cells for 3 hours, specific cell-killing was observed. If the exposure time was lengthened to 18 hours, however, nonspecific killing resulted. Incubation of the immunoconjugate with the nonspecific adsorbant Amberlite XAD-2 caused an average 30% decrease in the DXR-to-MoAb molar ratio, suggesting a population of drug that is tightly but noncovalently associated with MoAb.

Chemosensitivity assays were carried out as part of a tumor acquisition, propagation, and preservation program for cancer biotherapy. In addition to biopsy specimens, tumor cells propagated in culture or tumor xenografts grown in nude mice were submitted for chemosensitivity assay when sufficient biopsy material was unavailable. Chemosensitivity was tested utilizing the adhesive tumor cell culture system. A total of 154 specimens was submitted for testing; 96 specimens were assayed. Success rates were 55% for primary cancer biopsies, 67% for metastases, 69% for xenografts, and 70% for cell lines. There were no significant differences evident when the sensitivity to drugs of tumor cells originating from biopsies, xenografts, or tissue culture were compared. Sufficient data were available for 18 patients to compare clinical results of drug treatment with predictive results from the chemo-sensitivity assay. Assay results indicating insensitivity appeared to predict resistance; however, assays indicating sensitivity were not predictive. These results suggest that propagated tumor material, such as xenografts and cultured cell lines, may be useful when biopsy tissue is not available.

Immunization of congenitally athymic (nu/nu) and adult thymectomized, irradiated bone marrow, reconstituted (TxBm) mice with DNP5-thymosin (dinitrophenylated-bovine thymosin fraction 5) was found to elcit IgM and IgG anti-DNP plaque-forming cells in these animals. Further studies indicated that this response was antigen specific and not due to polyclonal activation. Since the hormonal properties of the thymosin were retained following linkage with hapten and DNP-thymosin was immunogenic in CBA/N and CBA/N female X DBA/2 male)F1 male mice, animals previously shown to have an X-linked inability to respond to thymus-independent antigens, it was concluded that DNP-thymosin functions both as a hormone and as a T-dependent antigen in eliciting an immune response in nu/nu and TxBm mice. Additional support for this conclusion was provided by the demonstration that DNP-thymosin could specifically prime for and elicit an anamnestic response in nu/nu mice. These results indicate that further investigation of the immune activities of DNP-thymosin may provide valuable insight in characterizing the maturation of helper T cells and their subsequent interaction with B cells.

Thymosin fraction 5 can induce the appearance of suppressor T cells capable of regulating the in vitro generation of cytotoxic T lymphocytes (CTL) in a 5-day allogeneic or syngeneic mixed lymphocyte-tumor culture (MLTC). Characterization of the suppressor cell population demonstrated it to be a nonadherent, cyclophosphamide-sensitive T cell. In addition, adult thymectomy (Tx) eliminated suppressor cell precursors in spleen, pointing to a direct thymic dependence of the population. Kinetic studies showed that the thymosin influence was necessary for at least the first 12 hr of culture in order for optimal suppression to occur. The in vitro-generated suppressor T cells were antigen specific and could be generated with spleen, thymus, or lymph node cell preparations, suggesting the widespread existence of a regulatory T-cell population under direct humoral thymic control.

Induction of differentiation in B lymphoma/leukemia cells with interleukins was compared with differentiation induced by phorbol ester (TPA) and pokeweed mitogen (PWM) or by 8-bromo-guanosine. Both cell surface changes and monoclonal immunoglobulin (Ig) secretion were followed as markers of differentiation. The results indicate great similarity in the differentiation patterns induced by interleukin-1 (IL-1), interleukin-2 (IL-2), and interleukin-4 (IL-4), with regard to Ig secretion and changes in surface markers. Induction of Ig secretion and surface marker changes by 8-bromo-guanosine was similar to that induced by TPA and PWM; however, for some markers, cell surface changes induced by TPA and PWM or by 8-bromo-guanosine were quite different from those induced by the three interleukins tested. Whereas all three interleukins stimulated the expression of CD5, PWM and TPA and 8-bromo-guanosine substantially decreased CD5 expression on B lymphoma cells. Differences were also observed in the effect on the expression of surface Ig and on the expression of CD19 and CD20. Interestingly, the three interleukins tested and 8-bromo-guanosine induced differentiation and Ig secretion within 24 to 48 hours with no prior activation by B-cell activators, such as anti-surface Ig antibody. These results suggest that leukemic B cells are arrested at a point distal to activation and first cell division. Moreover, the similarity in Ig secretion and surface changes induced by TPA and PWM or 8-bromo-guanosine suggest a similar pathway; however, this pathway is different from the differentiation signal induced by the three interleukins.

Thymosin alpha 1, an immune restorative polypeptide hormone, was synthesized in Escherichia coli by using recombinant DNA cloning techniques. Based on the known amino acid sequence, a gene coding for the thymosin alpha 1 polypeptide chain was designed and enzymatically assembled from chemically synthesized oligodeoxyribonucleotide fragments. The gene was ligated into plasmid pBR322 and placed under lac operon control, and N alpha-desacetylthymosin alpha 1 was expressed as part of a beta-galactosidase chimeric protein. Cyanogen bromide cleavage of this protein gave a mixture of polypeptides, among which thymosin alpha 1 activity was detected by radioimmunoassay (RIA). The E. coli product is identical with native thymosin alpha 1 isolated from calf thymus in the amino acid sequence but lacks the N-terminal acetyl group. Results of a guinea pig migration inhibition factor (MIF) assay, a terminal deoxyribonucleotidyl transferase (TdT) assay, and radioimmunoassay indicate that the N alpha-desacetylthymosin alpha 1 produced by deoxyribonucleic acid (DNA) cloning techniques has biological activity equivalent to that of the native hormone.

A new method has been characterized for the use of viable target cells as the solid phase for screening of hybridoma supernatants in a cell concentration fluorescence immunoassay (CCFIA). Briefly, the specific target antigen on the cells is bound by the monoclonal antibodies and revealed by use of a fluoresceinated second antibody. Separation of free from bound antibody is accomplished by filtration in the 0.2 micron filter-bottom wells of specialized assay plates. Processing is automated in a Pandex screen machine, resulting in numerical fluorescence values for each well. This method is rapid (under 1 h per 96-well plate), highly sensitive (down to 0.2 ng/ml) and sparing of target cells (0.3-2.5 X 10(4) cells per assay well). It has been applied to 37 different varieties of human solid tumor cells, as well as to human peripheral blood mononuclear cells. The cells used as targets for the characterization of this method were still capable of attachment and growth when recovered post-assay. This method was compared with a viable cell enzyme-linked immunosorbent assay (ELISA) method, showing similar sensitivity and greatly shortened assay time. Comparison of the results from this method with those obtained from flow cytometric analysis performed on viable cells showed close correlation, whereas a lower correlation was seen with immunohistochemical methods using acetone-fixed cells. Development of this method made it possible to rapidly screen many thousands of hybridoma supernatants and successfully select those which were specific for surface antigens on viable cells.

Recent reports 1-3 have proposed that T-lymphocytes (thymus derived) could be distinguished from B-lymphocytes (thymus independent) by examining their features under the scanning electron microscope. T-cells were designated as having relatively smooth surfaced cells, whereas B-cells had "hairy" surfaces with many microvilli. We have examined this hypothesis in congenitally athymic "nude" mice, animals lacking T-cells,4 and have not been able to confirm these reports. We have found that lymphocytes from nude (nu/nu) mice are indistinguishable from lymphocytes obtained from normal littermates (NLM) and CBA/J mice. We have found that in all the murine lymphoid tissue examined, including nude, the complete gamut of cell surface types, ranging from smooth to "hairy" are present. Our studies indicate that the proposed T- and B-cell classification based upon human surface morphology under the scanning electron microscope is questionable in a mouse model. It is presently unclear whether the smooth lymphocytes seen in nude mice are immature B-cells, pre-T-cells, or another unidentified population of cells.

Prior scanning electron microscope studies have indicated that T (thymus derived) lymphocytes appear "smooth" while human B (thymus independent) lymphocytes appear "hairy" with numerous microvilli covering their surfaces. A recent report (24) has raised some doubt as to the validity of classifying lymphocyte subpopulations on this purely morphologic basis. We have examined lymphocytes taken from congenitally athymic "nude" mice (lacking T cells) and compared them with those taken from normal littermates and CBA/J mice (both having T cell populations). We have determined that there are no distinguishable differences between the distribution of surface morphologies of lymphocytes from animals either with or without T and B cells. Our studies indicate that the classification of T and B cells, based on cell surface features, requires more than just finding out whether or not the cells are smooth or hairy.

Adoptive immunotherapy involving bolus-dose recombinant interleukin-2 (rIL-2) has been reported to induce tumor regression in some patients with cancer, but has been associated with severe fluid retention and cardiopulmonary stress. In an effort to preserve the efficacy but reduce the toxicity of this treatment, we used escalating doses of rIL-2 as a constant infusion rather than as a bolus dose. Forty-eight patients with advanced cancer received rIL-2 as a 24-hour infusion in five-day cycles separated by five-day periods of rest and leukapheresis. Eight patients were removed from the study before receiving cells activated in vitro. In the 40 who could be evaluated for their response, there were 13 partial responses (32.5 percent) and 2 minor responses. Partial responses were observed in Hodgkin's disease (one of one), non-Hodgkin's lymphoma (one of one), lung cancer (one of five), ovarian cancer (one of one), parotid cancer (one of two), renal cancer (three of six), and melanoma (five of ten). Responses were associated with a good performance status, a base-line lymphocyte count above 1400 per cubic millimeter, and an rIL-2-induced lymphocyte count of at least 6000. Optimal lymphocytosis required a priming dose of rIL-2 of 3 X 10(6) U per square meter of body-surface area per day, and 15 of 28 patients receiving this priming dose responded to treatment. A weight gain of more than 10 percent of total body weight (five patients) and dyspnea at rest (six patients) were unusual events restricted to patients with poorer pretreatment performance. We conclude that the administration of rIL-2 as a constant infusion may preserve the antineoplastic activity of adoptive immunotherapy while increasing the safety and comfort of patients.