Cytotoxic T lymphocytes do not appear to select for mutations in an immunodominant epitope of simian immunodeficiency virus gag

Studies to date assessing HIV escape from CTL in vivo have yielded conflicting results. Previous studies have demonstrated that simian immunodeficiency virus of macaques (SIVmac)-infected rhesus monkeys expressing the MHC class I allele Mamu-A*01 reproducibly develop a gag-specific CTL response limited to a 9-amino acid epitope of the SIVmac gag protein (residues 182-190 within peptide 11C). To determine whether CTL have a role in selecting for AIDS virus mutants, we examined mutations in SIVmac proviral DNA encoding this gag CTL epitope in PBL of infected rhesus monkeys. Three Mamu-A*01+ rhesus monkeys were infected with SIVmac and assessed for gag- and peptide 11C-specific CTL responses. This specific CTL response was maintained in two monkeys, but lost in the third animal 2 yr after infection. The generation of proviral gag mutations was then determined by sequencing 500-bp proviral fragments amplified from fresh PBL obtained from the monkeys more than 2.5 yr after infection. Although numerous point mutations were characterized in 131 polymerase chain reaction-generated clones of SIVmac gag, only four mutations within the gag CTL epitope-coding region of the genome were identified. Comparison of synonymous and nonsynonymous nucleotide substitutions in the regions encoding peptide 11C (p11C) and the flanking gag protein indicated a lack of selective pressure for viral mutations in the CTL epitope coding region. Interestingly, a predominant gag mutant encoding a single amino acid change in p11C was found in a monkey which lost its CTL activity. However, even in this setting there was no evidence for selection of mutations in the CTL epitope coding region when compared with the flanking region. Furthermore, synthetic peptides corresponding to all naturally occurring variants in the gag epitope-coding region were recognized by cloned and bulk cultured effector cells of the infected monkeys with persistent CTL. These results indicate that SIVmac gag- and p11C-specific CTL do not select for mutations in the immunodominant epitope-coding region and that the naturally occurring mutants do not appear to escape CTL recognition.

Vaccination of rhesus monkeys with synthetic peptide in a fusogenic proteoliposome elicits simian immunodeficiency virus-specific CD8+ cytotoxic T lymphocytes

An effective vaccine against the human immunodeficiency virus should be capable of eliciting both an antibody and a cytotoxic T lymphocyte (CTL) response. However, when viral proteins and peptides are formulated with traditional immunological adjuvants and inoculated via a route acceptable for use in humans, they have not been successful at eliciting virus-specific, major histocompatibility complex (MHC) class I-restricted CTL. We have designed a novel viral subunit vaccine by encapsulating a previously defined synthetic peptide CTL epitope of the simian immunodeficiency virus (SIV) gag protein within a proteoliposome capable of attaching to and fusing with plasma membranes. Upon fusing, the encapsulated contents of this proteoliposome can enter the MHC class I processing pathway through the cytoplasm. In this report, we show that after a single intramuscular vaccination, rhesus monkeys develop a CD8+ cell-mediated, MHC class I-restricted CTL response that recognizes the synthetic peptide immunogen. The induced CTL also demonstrate antiviral immunity by recognizing SIV gag protein endogenously processed by target cells infected with SIV/vaccinia recombinant virus. These results demonstrate that virus-specific, MHC class I-restricted, CD8+ CTL can be elicited by a safe, nonreplicating viral subunit vaccine in a primate model for acquired immune deficiency syndrome. Moreover, the proteoliposome vaccine formation described can include multiple synthetic peptide epitopes, and, thus, offers a simple means of generating antiviral cell-mediated immunity in a genetically heterogeneous population.

Receptors for IgA on phagocytic cells

IgA receptors have been detected on monocytes, polymorphonuclear neutrophils (PMNs) and eosinophils, and on phagocytic cells at mucosal sites. These receptors bind both secretory and serum forms of immunoglobulin A (IgA) and require the Ca2 region of the IgA molecule for ligand recognition. Monocytes and PMNs modulate their expression of the IgA receptor upon treatment with cytokines, such as granulocyto-macrophage colony-stimulating factor, and lipopolysaccharide. Purified IgA receptors appear as heavily glycosylated molecules with an average molecular weight of 60 kD, dropping to 32 and 36 kD upon treatment with N-glycanase. The cDNA sequence encoding the IgA receptor has been determined by expression cloning, and predicts that the receptor consists of two Ig-like extracellular domaines, a transmembrane region and a cytoplasmic tail of 41 residues. Ligation of IgA receptors on phagocytic cells by multivalent IgA complexes induces a variety of responses, including superoxide generation, release of inflammatory mediators, phagocytosis, and killing of various pathogenic microorganisms. Thus the apparent role of these receptors is to amplify the protective effects of the IgA antibody, a function of potential importance to mucosal defense.

[Effects of fertilization on yield of Asparagus cochinchinensis (Lour.) Merr]

The experiment revealed that the use of various kinds of fertilizers has apparent effect on the yield of Asparagus cochinchinensis during its growth period. Nitrogen fertilizer and compound fertilizer are suitable for the seeding period, while compound fertilizer, phosphorus and potassium fertilizers are suitable for the period of root forming. The quantity of fertilizer to be used depends on the growing and soil conditions.

Selenium content of goat milk and its distribution in protein fractions

This study reports on selenium distribution in goat milk. Skim milk was found to contain the major part (94%) of total milk selenium. The selenium distribution over casein and whey protein fractions depends on the separation method used, but irrespective of these methods, skim milk selenium is mainly associated with the casein fraction (greater than 69%). Approximately 9%, 7% and 24% of selenium is removed by dialysis (molecular cutoff 10-12 kDa) from skim milk, casein and whey respectively, indicating a major association of selenium with milk proteins. This observation is confirmed by selenium analysis of individual caseins and whey proteins isolated through ion-exchange chromatography and gel filtration. Selenium concentrations of the different isolated milk proteins show considerable variation (caseins: 294-550 ng Se/g; whey proteins: 217-457 ng Se/g).

Radioligand binding and inotropic effects of ryanodine in the cardiomyopathic Syrian hamster

We compared the radioligand-binding and inotropic effects of ryanodine [known specific regulator of sarcoplasmic reticulum (SR) calcium release channel] on BIO 14.6 cardiomyopathic Syrian hamsters with those on age-matched F1B controls. Scatchard analyses of [3H]ryanodine binding to cardiac membranes prepared from 1-2-month-old BIO 14.6 and F1B Syrian hamsters revealed the presence of a significant increase in binding capacity (Bmax = 942 +/- 49 vs. 567 +/- 33 fmol/mg protein) with no difference in affinity (KD = 3.9 +/- 0.4 vs. 3.5 +/- 0.5 nM, p less than 0.01). Ryanodine is a significantly less potent negative inotrope in isolated papillary muscles prepared from 1-2-month-old BIO 14.6 hamsters than in muscles from F1B controls (IC50 = 4.3 +/- 1 vs. 0.5 +/- 0.4 microM, p less than 0.05). Ryanodine was 200-fold less potent in the 4-6-month-old myopathic muscles than in controls (IC50 = 20 +/- 5 vs. 0.1 +/- 0.01 microM, p less than 0.01). A paradoxic positive inotropic effect of ryanodine observed in 4-6-month-old myopathic muscles at low concentrations was not seen in controls (ECmax = 126 +/- 5% at 1 +/- 0.1 x 10(-8) M). These data support the presence of a defect both biochemical and physiologic in the ryanodine-sensitive SR calcium release channel in the BIO 14.6 cardiomyopathic Syrian hamster. Purification, cloning, sequencing, and expression studies will be required to distinguish among primary, secondary, intrinsic, and regulatory defects in the ryanodine-sensitive SR calcium release channel in the cardiomyopathic Syrian hamster.

A monoclonal antibody specific for immunoglobulin A receptor triggers polymorphonuclear neutrophil superoxide release

An immunoglobulin M (IgM) monoclonal antibody, My43, specific for IgA Fc receptor (Fc alpha R) on human monocytes, bound to human polymorphonuclear neutrophils (PMNs) and inhibited their ability to bind IgA but not IgG. It was observed that the PMN oxidative burst was induced by both polymeric IgA and aggregated IgG, whereas IgM was without effect. The IgG-mediated oxidative burst was inhibited by anti-Fc gamma RII Fab and anti-Fc gamma RIII F(ab')2 but not by My43. Conversely, the IgA-mediated oxidative burst was inhibited by My43 but not by anti-Fc gamma RII or anti-Fc gamma RIII. When anti-Fc receptor monoclonal antibodies (mAbs) were used directly as ligands, it was observed that both anti-Fc gamma RII Fab and anti-Fc gamma RII F(ab')2 promoted the oxidative burst when cross-linked. Moreover, My43, when cross-linked with F(ab')2 antimouse IgM, also triggered the oxidative burst, whereas an IgM anti-CD15 mAb, PM81, did not stimulate function. This demonstrates that IgA receptors on PMNs are function-triggering molecules and that an anti-IgA receptor mAb may be substituted as a ligand.

[Biological characteristics of Cryptoporus volvatus (peck) Hubb., a medicinal fungus]

Through ecological investigations and experimental studies, it has been shown that C. volvatus is a fungus growing on decaying matter; the carbon source of culture medium comes from glucose, honey, fructose, mannitol, etc; and its nitrogen source from peptone, yeast powder, etc. The best ratio of carbon to nitrogen (C/N) is 20-25: 1, optimum pH 5.5-6.5 and optimal temperature 25-30 degrees C.

Channel reconstitution in liposomes and planar bilayers with HPLC-purified MIP26 of bovine lens

The major intrinsic protein (MIP26) of bovine lens membranes, purified by HPLC, was incorporated into liposomes and planar bilayers. Permeability of MIP26 channels was studied in liposomes by a spectrophotometric osmotic-swelling assay, and channel electrical properties were monitored in planar bilayers following liposome fusion. Particle formation in liposomes was determined by freeze fracture. MIP26 channels were permeable to KCl and sucrose. In planar bilayers, channel-conductance transitions were observed only after addition of liposomes to both chambers and with voltages greater than +/- 20 mV. Channel open probability decreased progressively as voltage increased, and an open probability of 50% was at 60-80 mV, indicating that the channels are voltage dependent. Histograms of single-channel current amplitudes at 80 mV showed a Gaussian distribution that peaked at 10 pA (approximately 120 pS), after subtraction of 1 pA baseline current. Frequency distributions of open and closed times at 80 mV were single exponential functions with time constants of 0.13 and 1.9 sec, respectively. Open time constants ranged from 0.1 to 0.3 sec, and closed time constants ranged from 1 to 7 sec. Cs+ did not decrease conductance, but reduced mean open time from 0.2 to 0.038 sec and mean closed time from 1.5 to 0.38 sec. The increase in channel flickering with Cs+ occurred in bursts. TEA affected neither conductance nor kinetics. Channel events were also observed in Na+ solutions (zero K+). These data indicate that MIP26 channels are not K(+)-selective channels. Channel characteristics such as: permeability to molecules larger than small ions, conductance greater than 100 pS, long open and closed time constants, etc., are similar to those of gap junction channels.

[Identification of Yi nationality's secret recipe for treating snakebite]

The authors have investigated and found an effective secret recipe for the treatment of snakebite in Mabian, an autonomous county of the Yi nationality in Sichuan Province. Morphologic identification has shown that the recipe is composed of the herb of Pedicularis muscicola and the rhizome of Polygonum viviparum in the ratio of one to one. To facilitate further application, popularization and improvement of the recipe, its histological characteristics have also been studied microscopically.

Immunization of simian immunodeficiency virus-infected rhesus monkeys with soluble human CD4 elicits an antiviral response

Since the CD4 molecule is a high-affinity cell-surface receptor for the human immunodeficiency virus (HIV), it has been suggested that a soluble truncated form of CD4 may compete with cell-surface CD4 for HIV binding and thus be of use in the therapy of AIDS. We have utilized the simian immunodeficiency virus of macaques (SIVmac)-infected rhesus monkeys to explore another possible therapeutic application of CD4 in AIDS--the use of recombinant soluble CD4 (rsCD4) as an immunogen. SIVmac-infected rhesus monkeys immunized with human rsCD4 developed not only an anti-human CD4 but also an anti-rhesus monkey CD4 antibody response. Coincident with the generation of this antibody response, SIVmac could not be isolated easily from peripheral blood lymphocytes and bone marrow macrophages of these animals. Furthermore, the decreased number of both granulocyte/macrophage and erythrocyte colonies grown from the bone marrow of these immunized monkeys rose to normal levels. These findings suggest that a modified human CD4 molecule serving as an immunogen might elicit an antibody response in man that could induce a beneficial therapeutic response in HIV-infected individuals.

Recombinant virus vaccine-induced SIV-specific CD8+ cytotoxic T lymphocytes

Evidence indicates that cytotoxic T lymphocytes (CTLs) may be important in containing the spread of the human immunodeficiency virus (HIV) in the infected host. Although the use of recombinant viruses has been proposed as an approach to elicit protective immunity against HIV, the ability of recombinant viral constructs to elicit CD8+ CTL responses in higher primates has never been demonstrated. A live recombinant virus, vaccinia-simian immunodeficiency virus of macaques (SIVmac), was used to determine whether such a genetically restricted, T lymphocyte-mediated antiviral response could be generated in a primate. Vaccinia-SIVmac vaccination elicited an SIVmac Gag-specific, CD8+ CTL response in rhesus monkeys. These CTLs recognized a peptide fragment that spans residues 171 to 195 of the Gag protein. The rhesus monkey major histocompatibility complex (MHC) class I gene product restricting this CTL response was defined. Both the vaccinated and SIVmac-infected monkeys that shared this MHC class I gene product developed CTLs with the same Gag epitope specificity. These findings support the use of recombinant virus vaccines for the prevention of HIV infections in humans.

[Pharmacognostical study on the Chinese drug nanshashen]

The Chinese drug nanshashen is taken from a variety of plants. In this paper, 11 kinds of nanshashen derived from 11 plants of Adenophora have been studied in their pharmacognostical characters and microproperties. A key has been compiled based on the experimental results.

Expression cloning of a human Fc receptor for IgA

IgA, the predominant isotype in secretions, mediates the neutralization and removal of environmental antigens from mucosal sites. Although cell surface receptors for the Fc region of IgA (Fc alpha R) have been implicated in a variety of immune effector mechanisms, the molecular features of Fc alpha R remain only marginally characterized. In this report, we describe the isolation of a clone from a myeloid cell line cDNA library that directs the expression of a cell surface molecule with IgA binding specificity. The cDNA encodes a peptide of Mr 30,000 including a putative transmembrane region with features atypical of conventional membrane-anchored proteins. Databank searches indicate that the human myeloid cell Fc alpha R sequence is unique, is a member of the immunoglobulin gene superfamily, and is related to Fc receptors for IgG (Fc gamma RI, II, and III) and IgE (Fc epsilon RI).

Evaluation of the antibody-dependent cytotoxic capabilities of individual human monocytes. Role of Fc gamma RI and Fc gamma RII and the effects of cytokines at the single cell level

In this report we present evidence that not all human peripheral blood monocytes mediate antibody-dependent cellular cytotoxicity (ADCC), and that this function may be determined on an individual cell by both the type and level of expression of FcR, and by the state of cellular activation and/or differentiation. Although the diverse range of effector and regulatory functions performed by human monocytes suggests the possibility of distinct subsets, it is not clear whether observed functional heterogeneity reflects the presence of true monocyte subpopulations, or whether this diversity represents a continuum of maturational states present in the peripheral circulation. In an attempt to address this question, we investigated the ability of human monocytes to carry out ADCC at the single cell level, with emphasis on the role of the three FcR for IgG (Fc gamma RI, Fc gamma RII, and Fc gamma RIII) in mediating cytotoxicity. Using a modified plaque assay, 58.3% +/- 4.9 of freshly isolated monocytes mediated ADCC, as evidenced by the formation of lytic plaques in monolayers of ox erythrocyte (oxE) target cells. Significant increases in the number of plaque-forming cells were observed after positive selection by flow microfluorimetry for those monocytes expressing high levels of Fc gamma RI and Rc gamma RII, but not Fc gamma RIII. Bispecific antibodies composed of Fab fragments of anti-oxE antibody covalently coupled to Fab fragments of anti-Fc gamma R antibodies were used to independently evaluate the ability of Fc gamma RI, Fc gamma RII, and Fc gamma RIII to mediate single cell cytotoxicity. Significant increases in the number of plaque-forming cells were observed in the presence of anti-Fc gamma RI x anti-oxE and anti-Fc gamma RII x anti-oxE bispecific antibodies, confirming the efficiency of Fc gamma RI and Fc gamma RII as cytotoxic trigger molecules on human monocytes. Incubation of monocytes with purified rIFN-gamma and granulocyte macrophage-CSF, but not IL-2, IL-3, IL-4, IL-6, or TNF-alpha, also resulted in significant increases in the number of monocytes mediating cytotoxicity, suggesting that cytotoxic ability at the single cell level may be influenced by factors which effect monocyte activation and differentiation, respectively. Overall, these studies demonstrate that freshly isolated human monocytes are heterogeneous in their ability to mediate ADCC, and suggest that this functional diversity arises not from discrete subpopulations of cells, but from a continuum of maturational/activational states present within the peripheral circulation.

Evaluation of the antibody-dependent cytotoxic capabilities of individual human monocytes. Role of Fc gamma RI and Fc gamma RII and the effects of cytokines at the single cell level

In this report we present evidence that not all human peripheral blood monocytes mediate antibody-dependent cellular cytotoxicity (ADCC), and that this function may be determined on an individual cell by both the type and level of expression of FcR, and by the state of cellular activation and/or differentiation. Although the diverse range of effector and regulatory functions performed by human monocytes suggests the possibility of distinct subsets, it is not clear whether observed functional heterogeneity reflects the presence of true monocyte subpopulations, or whether this diversity represents a continuum of maturational states present in the peripheral circulation. In an attempt to address this question, we investigated the ability of human monocytes to carry out ADCC at the single cell level, with emphasis on the role of the three FcR for IgG (Fc gamma RI, Fc gamma RII, and Fc gamma RIII) in mediating cytotoxicity. Using a modified plaque assay, 58.3% +/- 4.9 of freshly isolated monocytes mediated ADCC, as evidenced by the formation of lytic plaques in monolayers of ox erythrocyte (oxE) target cells. Significant increases in the number of plaque-forming cells were observed after positive selection by flow microfluorimetry for those monocytes expressing high levels of Fc gamma RI and Rc gamma RII, but not Fc gamma RIII. Bispecific antibodies composed of Fab fragments of anti-oxE antibody covalently coupled to Fab fragments of anti-Fc gamma R antibodies were used to independently evaluate the ability of Fc gamma RI, Fc gamma RII, and Fc gamma RIII to mediate single cell cytotoxicity. Significant increases in the number of plaque-forming cells were observed in the presence of anti-Fc gamma RI x anti-oxE and anti-Fc gamma RII x anti-oxE bispecific antibodies, confirming the efficiency of Fc gamma RI and Fc gamma RII as cytotoxic trigger molecules on human monocytes. Incubation of monocytes with purified rIFN-gamma and granulocyte macrophage-CSF, but not IL-2, IL-3, IL-4, IL-6, or TNF-alpha, also resulted in significant increases in the number of monocytes mediating cytotoxicity, suggesting that cytotoxic ability at the single cell level may be influenced by factors which effect monocyte activation and differentiation, respectively. Overall, these studies demonstrate that freshly isolated human monocytes are heterogeneous in their ability to mediate ADCC, and suggest that this functional diversity arises not from discrete subpopulations of cells, but from a continuum of maturational/activational states present within the peripheral circulation.

Exclusion mapping of 12 X-linked disease loci and 10 DNA probes from the long arm of the X-chromosome

Specific chromosome rearrangements associated with disease entities are invaluable resources for physical mapping. A deletion on the X chromosome of a male leads to the nullisomy for X-linked genes, resulting in the onset of genetic diseases and/or the absence of the DNA probe detectable sequences. This permits the localization of these loci within the deleted area. On the other hand, the region for some other X-linked loci can be excluded from the deleted area according to the absence of the characteristic symptoms of the disease and/or the presence of the hybridization signals. An interstitial deletion on the long arm of the X chromosome of a male has been characterized by high resolution banding. The karyotype of the proband is 46,Y,del(X)(pter----q21.1::q21.33----qter). The regions for 12 X-linked disease loci as well as 10 DNA probes are excluded from the deleted area, and localized either proximally or distally to the deletion. The results also reveal a controversy in the present linkage data concerning the assignment of these loci.

A deletion panel of the long arm of the X chromosome: subregional localization of 22 DNA probes

Two males and two females with different but overlapping deletions on the proximal long arm of the X chromosomes have been investigated. Their karyotypes, which have been well characterized by high resolution banding techniques, are 46,Y,del(X)(pter----q21.1::q21.33----qter); 46,Y,del(X)(pter----q21.2::q21.31----qter); 46,X,del(X)(pter----q21.31::q24.3----qter) and 46,X,del(X)(pter----q21.1:). A deletion panel, which makes it possible to subdivide the long arm of the X chromosome into seven subregions, has been established using the genomic DNA from the four families, and applied to the fine subregional localization of the loci for 22 DNA probes. Based on the results obtained, the possible location of the loci in question has been narrowed down considerably, in some cases to an area of only 5% of the previously assigned region; hybridization to Southern blots of a panel with well-characterized chromosome deletions is thus a powerful means of localizing DNA probes, especially with respect to the X probes.

[Relation of tongue color changes and red-cell immune adherence activity in patients with malignant bone tumor]

This article presents that preliminary study on the changes of the tongue colour and the red-cell immune adherence (RCIA) activity in 40 patients with malignant bone tumor, as compared with 40 healthy persons. The results showed that the rate of erythrocyte C3b receptor yeast rosette were no statistically significant different between the pink and the crimson tongues in the bone tumor group and control group (P greater than 0.05). It appeared RCIA activity was no depression in the patients with malignant bone tumor during pink and crimson tongue. In the bone tumor group with the pale and the cyanotic tongues, the rate of erythrocyte C3b receptor yeast rosette and erythrocyte immune complex rosette was significantly lower than that of the control group (P less than 0.05, P less than 0.01). It appeared that RCIA activity in these patients was markedly impaired. The authors suggested that the tongue colour changes in the patients with malignant bone tumors could roughly reflect the level of RCIA activity. This phenomenon is beneficially to predict the body capacity against the malignant tumor.

Human alveolar macrophage FcR-mediated cytotoxicity. Heteroantibody- versus conventional antibody-mediated target cell lysis

Human alveolar macrophage have three distinct receptors for IgG: FcRI, FcRII, and FcRIII. In order to compare the ability of these receptors to mediate target cell lysis, three different assay systems were examined. First, we studied lysis of chicken E (CE) opsonized with heteroantibodies, which are synthetic antibodies composed of Fab fragments with anti-FcR activity covalently linked to Fab fragments with anti-CE activity. We found alveolar macrophage readily lysed heteroantibody-opsonized CE via each of the three FcR classes (FcRI, 20 +/- 5%; FcRII, 27 +/- 7%; and FcRIII, 13 +/- 13%, p less than 0.05). Non-FcR-dependent lysis of anti-beta 2-microglobulin x anti-CE heteroantibody-opsonized CE was not detected. Second, lysis of hybridoma cell lines bearing anti-FcR antibodies on their cell surface was examined to assess killing of "tumor-like" target cells. Whereas peripheral blood monocytes and lymphocytes were able to lyse hybridoma cell lines bearing surface anti-FcR mAb, alveolar macrophages were not. Third, activity of alveolar macrophage FcR was examined in a conventional antibody-dependent cellular cytotoxicity assay by using O+ (R1,R2) human RBC opsonized with human anti-D and anti-CD serum as target cells. We found lysis of anti-D and anti-CD opsonized human RBC was mediated exclusively via FcRI. No activity of FcRII or FcRIII was detected in these latter assays even if performed under conditions that impair FcRI activity. Thus, all three FcR present on alveolar macrophage mediate lysis of heteroantibody-opsonized CE; in contrast, with the use of a conventional antibody-dependent cellular cytotoxicity assay, only FcRI activity was detected. We were unable to demonstrate lysis of anti-FcR-bearing hybridoma cell lines by alveolar macrophages.

Human alveolar macrophage FcR-mediated cytotoxicity. Heteroantibody- versus conventional antibody-mediated target cell lysis

Human alveolar macrophage have three distinct receptors for IgG: FcRI, FcRII, and FcRIII. In order to compare the ability of these receptors to mediate target cell lysis, three different assay systems were examined. First, we studied lysis of chicken E (CE) opsonized with heteroantibodies, which are synthetic antibodies composed of Fab fragments with anti-FcR activity covalently linked to Fab fragments with anti-CE activity. We found alveolar macrophage readily lysed heteroantibody-opsonized CE via each of the three FcR classes (FcRI, 20 +/- 5%; FcRII, 27 +/- 7%; and FcRIII, 13 +/- 13%, p less than 0.05). Non-FcR-dependent lysis of anti-beta 2-microglobulin x anti-CE heteroantibody-opsonized CE was not detected. Second, lysis of hybridoma cell lines bearing anti-FcR antibodies on their cell surface was examined to assess killing of "tumor-like" target cells. Whereas peripheral blood monocytes and lymphocytes were able to lyse hybridoma cell lines bearing surface anti-FcR mAb, alveolar macrophages were not. Third, activity of alveolar macrophage FcR was examined in a conventional antibody-dependent cellular cytotoxicity assay by using O+ (R1,R2) human RBC opsonized with human anti-D and anti-CD serum as target cells. We found lysis of anti-D and anti-CD opsonized human RBC was mediated exclusively via FcRI. No activity of FcRII or FcRIII was detected in these latter assays even if performed under conditions that impair FcRI activity. Thus, all three FcR present on alveolar macrophage mediate lysis of heteroantibody-opsonized CE; in contrast, with the use of a conventional antibody-dependent cellular cytotoxicity assay, only FcRI activity was detected. We were unable to demonstrate lysis of anti-FcR-bearing hybridoma cell lines by alveolar macrophages.