Predation: Prey plumage adaptation against falcon attack.

Several plumage types are found in feral pigeons (Columba livia), but one type imparts a clear survival advantage during attacks by the swiftest of all predators--the peregrine falcon (Falco peregrinus). Here we use quantitative field observations and experiments to demonstrate both the selective nature of the falcon's choice of prey and the effect of plumage coloration on the survival of feral pigeons. This plumage colour is an independently heritable trait that is likely to be an antipredator adaptation against high-speed attacks in open air space.

Do responses of galliform birds vary adaptively with predator size?

Past studies of galliform anti-predator behavior show that they discriminate between aerial and ground predators, producing distinctive, functionally referential vocalizations to each class. Within the category of aerial predators, however, studies using overhead models, video images and observations of natural encounters with birds of prey report little evidence that galliforms discriminate between different raptor species. This pattern suggests that the aerial alarm response may be triggered by general features of objects moving in the air.

Rapid acquisition of an alarm response by a neotropical primate to a newly introduced avian predator.

Predation is an important selective pressure in natural ecosystems. Among non-human primates, relatively little is known about how predators hunt primate prey and how primates acquire adaptive responses to counteract predation. In this study we took advantage of the recent reintroduction of radio-tagged harpy eagles (Harpia harpyja) to Barro Colorado Island (BCI), Panama to explore how mantled howler monkeys (Alouatta palliata), one of their primary prey, acquire anti-predator defences.

Rational design of a potent, long-lasting form of interferon: a 40 kDa branched polyethylene glycol-conjugated interferon alpha-2a for the treatment of hepatitis C.

A potent, long-lasting form of interferon alpha-2a mono-pegylated with a 40 kilodalton branched poly(ethylene glycol) was designed, synthesized, and characterized. Mono-pegylated interferon alpha-2a was comprised of four major positional isomers involving Lys31, Lys121, Lys131, and Lys134 of interferon. The in vitro anti-viral activity of pegylated interferon alpha-2a was found to be only 7% of the original activity.

A second-generation enzyme immunoassay for detection of antibodies to IFN-alpha.

We have developed a solid-phase enzyme-linked immunoassay (EIA) for detecting antibodies to interferon-alpha2 (IFN-alpha2) in serum or plasma. In this assay, based on the sandwich principle, the capture antigen, IFN-alpha2, is covalently bound to the wells in 96-well plates. This novel procedure offers considerable advantages over the antigen binding by passive adsorption used in most previous EIA.

Nitric oxide synthase induction in lines of macrophages from different anatomical sites.

Induction of nitric oxide synthase (iNOS) and nitric oxide (NO) production have been demonstrated using three macrophage cell lines from different anatomical sites, which had been immortalized using a rapid and convenient procedure previously described. Lysis of tumor cells presumably was caused by NO accumulation in the supernatants of cultures of the three cell lines after induction with a mixture of recombinant murine interferon gamma (rMuIFNgamma) and lipopolysaccharide (LPS). Induction by these two biological response modifiers (BRM) caused lysis of tumor cells and was repressed by addition of 1 microM (final concentration) of methyl-L-arginine (MMA) to the mixture during induction of the enzyme.

Interferon immunogenicity: preclinical evaluation of interferon-alpha 2a.

A preclinical evaluation of the immunogenicity of various preparations of interferon-alpha (IFN-alpha) was performed with in vitro and in vivo animal models. The distribution of genes for IFN-alpha 2a, IFN-alpha 2b, and IFN-alpha 2c in various cell populations and the response of human T cell clones to IFN-alpha peptides were investigated. The immunogenicity of IFN-alpha in IFN-alpha 2b transgenic mice and factors that influence the immunogenicity of IFN-alpha in normal mice were also studied.

Positional isomers of monopegylated interferon alpha-2a: isolation, characterization, and biological activity.

The success of recombinant interferon alpha in the clinic in part is limited by two properties of the protein: short serum half-life and immunogenicity. To improve these properties, interferon alpha-2a was conjugated with polyethylene glycol (PEG-5000). A homogeneous preparation of monopegylated interferon alpha-2a was subjected to vigorous analytical and activity characterization.

Choroidal concentration of interferon after retrobulbar injection.

Purpose: To determine whether recombinant human interferon alpha-2a (IFN alpha-2a) would diffuse into the choroid in significant amounts from a retrobulbar depot.

Methods: One million international units of IFN alpha-2a were injected into the retrobulbar space of the eyes of 17 rabbits, and choroidal and serum concentrations were measured at 1, 2, 4, 8, 12, and 24 hours. The same dose of IFN alpha-2a was injected subcutaneously into 10 rabbits, and choroidal and serum concentrations were measured at the same intervals for comparison.

Antitumor activity of interleukin 12 in preclinical models.

Interleukin 12 (IL-12) is a heterodimeric cytokine with a number of biological effects that are consistent with its potential role as an antitumor agent. The antimetastatic and antitumor activities of IL-12 have been demonstrated in a number of murine tumor models. Both the inhibition of established experimental pulmonary or hepatic metastases and a reduction in spontaneous metastases have been achieved by treatment with murine IL-12.

In vivo immortalization of murine peritoneal macrophages: a new rapid and efficient method for obtaining macrophage cell lines.

Although several murine macrophage (m phi) cell lines from different sites have previously been obtained by in vitro infection with the J2 murine retrovirus, which carries the v-raf and v-myc oncogenes, it was not possible to immortalize thioglycolate-elicited peritoneal macrophages (Pm phi s) by this in vitro procedure. A technique utilizing in vivo injection of the J2 virus has been developed to overcome this problem. The J2 virus immortalized Pm phi s in a very efficient manner in vivo because no exogenous growth factors were required for the in vitro proliferation of these cells and numerous continuous cloned cell lines were readily established.

Tumoricidal alveolar macrophage and tumor infiltrating macrophage cell lines.

Continuous alveolar macrophage (AM) and tumor-infiltrated (TIM) cell lines have been generated from C57B16J mice by in vitro infection with the J2 retrovirus carrying the v-raf and v-myc oncogens. Four cloned AM cell lines (AMJ2-C8, AMJ2-C10, AMJ2-C11, AMJ2-C20) and 3 cloned TIM cell lines (TIMJ2-C4, TIMJ2-C7 and TIMJ2-C15) were expanded for further characterization. Flow cytometry detected the product of the raf gene in the cytoplasm of all these cell lines.

Tumoricidal activity and cytokine secretion by tumor-infiltrating macrophages.

Murine macrophages from different anatomical sites were compared for their ability to become tumoricidal and to secrete interleukin-1 (IL-1) and tumor necrosis factor (TNF) following stimulation in vitro by several biological response modifiers (BRM). Peritoneal macrophages (PM), alveolar macrophages (AM), and tumor-infiltrating-macrophages (TIM), isolated from B16F10 melanoma colonies in the lung, were incubated overnight with BRM [recombinant murine interferon gamma (rMulFN-gamma), lipopolysaccharide (LPS), muramyl dipeptide (MDP)], either alone or in combination. PM exhibited an increased cytotoxic response following incubation with LPS or rMuIFN-gamma but not with MDP.

Incidence and clinical significance of neutralizing antibodies in patients receiving recombinant interferon-alpha 2a.

In clinical trials with a range of doses of recombinant interferon-alpha 2a, we observed a 25% overall incidence of neutralizing antibody development. Careful data analysis did not reveal a relationship between antibody development and therapeutic response. Of 752 patients evaluable for antibody development and clinical response, 31% of the antibody-positive patients and 28% of the antibody-negative patients had therapeutic responses.

Recombinant interferon alfa-2a in metastatic renal cell carcinoma: assessment of antitumor activity and anti-interferon antibody formation.

Twenty-one patients with advanced, measurable, renal cell carcinoma (RCC) were administered recombinant interferon alfa-2a (rIFN-alpha 2a) (Roferon-A; Roche Laboratories, Nutley, NJ) intramuscularly beginning at 3 x 10(6) units and escalating to 36 x 10(6) units, 5 d/wk for a total induction period of 14 weeks. rIFN-alpha 2a antibody production was measured using an enzyme immunoassay (EIA). Those sera found to be positive for presence of antibody by the EIA were tested for the presence of neutralizing antibodies (NA) by an antiviral neutralization bioassay (ANB).

Normal human keratinocytes contain an interferon-like protein that may modulate their growth and differentiation.

Epidermal growth and differentiation is a complex process which depends upon a balance between positive and negative growth signals, and in normal skin the majority of the cells in the germinative basal layer do not proliferate unless stimulated. Using the indirect immunofluorescent method, it can be demonstrated that purified polyclonal epidermis in cross sections of normal skin and to the basal layer of cultured keratinocyte colonies. Furthermore, extracts of keratinocyte cultures contain interferon bioactivity.

The detection of antibodies to recombinant interferon alfa-2a in human serum.

Three different procedures have been used for detecting antibodies to Roferon-A (recombinant human interferon alfa-2a, rHuIFN alpha-2a) in the serum of patients who received this interferon as part of ongoing clinical trials: an antiviral neutralization bioassay (ANB), the standard method recommended by the World Health Organization (WHO), and the more recently developed radioimmunoassay (RIA) and enzymeimmunoassay (EIA). Although the three tests are based on different principles, the correlation among them was excellent. The assays show differences in sensitivities with the ANB being the least sensitive of the three.

Incidence and clinical significance of neutralizing antibodies in patients receiving recombinant interferon alfa-2a by intramuscular injection.

More than 1600 patients with neoplastic disorders have received recombinant human interferon alfa-2a (Roferon-A, Hoffmann-La Roche, Nutley, NJ) as part of ongoing or completed clinical trials. In this report, the efficacy of interferon alfa-2a therapy was compared with the incidence of antibodies to this interferon in 617 patients who received the drug by intramuscular administration. Antibody measurements were performed using a highly sensitive enzyme immunoassay, and an interferon antiviral neutralization bioassay.

A sensitive radioimmunoassay for detection of antibodies to recombinant human interferon-alpha A.

A radioimmunoassay (RIA) for the detection of antibodies to recombinant human leukocyte interferon A (rHuIFN-alpha A) in human serum has been developed and validated against the standard antiviral neutralization bioassay (ANB). The assay measures the binding of 125I-labeled rHuIFN-alpha A to immunoglobulins in serum. Aliquots of patients' sera are incubated with 125I-rHuIFN-alpha A and the complexes formed between antibodies in the sera and the 125I-rHuIFN-alpha A are precipitated with goat anti-human IgG serum.

Normal human epidermis contains an interferon-like protein.

Interferons have been postulated to participate in growth regulation of normal body tissues and are known to inhibit growth of human epidermal keratinocytes in vitro. Polyclonal antibodies to recombinant human interferon-alpha, purified by passage over an affinity column (Sepharose coupled to the recombinant interferon), used in the indirect immunofluorescent method specifically stained the proliferative (basal) compartment of human epidermis in histological cross-sections of normal skin and in cultured keratinocyte colonies. Extracts prepared from healthy nonvirally infected keratinocyte cultures contained interferon activity as determined by viral plaque inhibition assay.

Use of 125I-interferons in pharmacokinetic and tissue distribution studies.

The in vivo fate of radiolabeled recombinant human leukocyte A interferon (125I-rIFN-alpha A) and intramolecular hybrid A/D (125I-rIFN-alpha A/D Bgl) were studied, following iv injection into CD1 mice. Trichloroacetic acid (TCA) precipitable radioactivity, as well as antiviral activity, were measured in sera and several organ extracts. The results obtained by bioassay were very similar to those obtained by measuring the TCA precipitable radioactivity.

Antibodies to human leucocyte interferons in cancer patients.

During the course of clinical investigation of partly purified human leucocyte interferon (IFN) prepared at the Finnish Red Cross (PIF), neutralising IgG antibodies to human leucocyte IFN were detected in the sera of 3 patients with cancer. In 2 of these patients, the antibodies were detected in serum before treatment with PIF. In the third patient antibodies developed during the course of treatment.

Relationship between binding affinities to cellular retinoic acid-binding protein and in vivo and in vitro properties for 18 retinoids.

A new rapid assay has been developed for measurement of the binding of [3H]retinoic acid to cellular retinoic acid-binding protein. The assay, which uses activated charcoal for the separation of bound from unbound retinoic acid, was used to determine the concentration required to inhibit the binding of [3H]retinoic acid to cellular retinoic acid-binding protein by 50% for 18 retinoids with free carboxylic acid groups. Partially purified cellular retinoic acid-binding proteins isolated from rat testes and carcinogen-induced rat mammary tumors were used for these determinations.