Remote Individual Addressing of Quantum Emitters with Chirped Pulses.

We propose to use chirped pulses propagating near a band gap to remotely address quantum emitters. We introduce a particular family of chirped pulses that dynamically self-compress to subwavelength spot sizes during their evolution in a medium with a quadratic dispersion relation. We analytically describe how the compression distance and width of the pulse can be tuned through its initial parameters. We show that the interaction of such pulses with a quantum emitter is highly sensitive to its position due to effective Landau-Zener processes induced by the pulse chirping. Our results propose pulse engineering as a powerful control and probing tool in the field of quantum emitters coupled to structured reservoirs.

Nanometre-scale thermometry in a living cell.

Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical and chemical research. Possibilities range from the temperature-induced control of gene expression and tumour metabolism to the cell-selective treatment of disease and the study of heat dissipation in integrated circuits. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the subcellular level. Here we demonstrate a new approach to nanoscale thermometry that uses coherent manipulation of the electronic spin associated with nitrogen-vacancy colour centres in diamond. Our technique makes it possible to detect temperature variations as small as 1.8 mK (a sensitivity of 9 mK Hz(-1/2)) in an ultrapure bulk diamond sample. Using nitrogen-vacancy centres in diamond nanocrystals (nanodiamonds), we directly measure the local thermal environment on length scales as short as 200 nanometres. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the subcellular level, enabling unique potential applications in life sciences.

Circumventing Magnetostatic Reciprocity: A Diode for Magnetic Fields.

Lorentz reciprocity establishes a stringent relation between electromagnetic fields and their sources. For static magnetic fields, a relation between magnetic sources and fields can be drawn in analogy to the Green's reciprocity principle for electrostatics. So far, the magnetostatic reciprocity principle remains unchallenged and the magnetostatic interaction is assumed to be symmetric (reciprocal). Here, we theoretically and experimentally show that a linear and isotropic electrically conductive material moving with constant velocity is able to circumvent the magnetostatic reciprocity principle and realize a diode for magnetic fields. This result is demonstrated by measuring an extremely asymmetric magnetic coupling between two coils that are located near a moving conductor. The possibility to generate controlled unidirectional magnetic couplings implies that the mutual inductances between magnetic elements or circuits can be made extremely asymmetric. We anticipate that this result will provide novel possibilities for applications and technologies based on magnetically coupled elements and might open fundamentally new avenues in artificial magnetic spin systems.

Critical Thermalization of a Disordered Dipolar Spin System in Diamond.

Statistical mechanics underlies our understanding of macroscopic quantum systems. It is based on the assumption that out-of-equilibrium systems rapidly approach their equilibrium states, forgetting any information about their microscopic initial conditions. This fundamental paradigm is challenged by disordered systems, in which a slowdown or even absence of thermalization is expected. We report the observation of critical thermalization in a three dimensional ensemble of ∼10^{6} electronic spins coupled via dipolar interactions. By controlling the spin states of nitrogen vacancy color centers in diamond, we observe slow, subexponential relaxation dynamics and identify a regime of power-law decay with disorder-dependent exponents; this behavior is modified at late times owing to many-body interactions. These observations are quantitatively explained by a resonance counting theory that incorporates the effects of both disorder and interactions.

Ultrafocused Electromagnetic Field Pulses with a Hollow Cylindrical Waveguide.

We theoretically show that a dipole externally driven by a pulse with a lower-bounded temporal width, and placed inside a cylindrical hollow waveguide, can generate a train of arbitrarily short and focused electromagnetic pulses. The waveguide encloses vacuum with perfect electric conducting walls. A dipole driven by a single short pulse, which is properly engineered to exploit the linear spectral filtering of the cylindrical hollow waveguide, excites longitudinal waveguide modes that are coherently refocused at some particular instances of time, thereby producing arbitrarily short and focused electromagnetic pulses. We numerically show that such ultrafocused pulses persist outside the cylindrical waveguide at distances comparable to its radius.

Factors associated with therapeutic success in HIV-positive individuals in southern Brazil.

WHAT IS KNOWN AND OBJECTIVE: Therapeutic success is characterized by undetectable viral load, immune reconstitution confirmed by CD4+ T-cell count and no clinical manifestations of disease. High treatment adherence is a major determinant of therapeutic success that needs prevention of viral replication, allowing immune reconstitution. Adherence to treatment <95% has been associated with both immune and viral failure. The objective of this study was to evaluate factors associated with therapeutic success in adult patients on highly active antiretroviral therapy (HAART) in a specialized centre for HIV-AIDS in southern Brazil, being defined therapeutic success as achieving and maintaining undetectable viral load, stable immune status (CD4+ T lymphocyte count ≥200 cells/mm(3) ) and adherence to HAART ≥ 95%. METHODS: We conducted a historical cohort study nested in the PC-HIV randomized clinical trial of PC-HIV. We included adults who were on HAART at Pelotas HIV/AIDS Assistance Service between June 2006 and July 2007 and for whom information on treatment adherence, viral load and CD4+ cell count was available. Pregnant women were excluded. We obtained clinical data from medical records and socio-demographic information in an interview. Therapeutic success was defined as achieving and maintaining undetectable viral load, stable immune status (CD4+ T lymphocyte count ≥200 cells/mm(3) ) and adherence to HAART ≥95%. RESULTS AND DISCUSSION: We included 136 patients (60% male) in the cohort study. Mean age was 40 ± 10 years, and median treatment duration was 59 months (IQR 25-93). Family income varied from 0 to 8 times the minimum wage (IQR 1·0-2·3). Therapeutic success was achieved by 90% (122 patients), and it was associated with previously undetectable viral load (PR = 1·30; 95% CI = 1·13-1·49) and treatment adherence prior to study entry (PR = 1·34; 95% CI = 1·07-1·69), independently of sex, age and previous immune status. WHAT IS NOW AND CONCLUSION: When undetectable viral load, CD4+ cell count ≥200 cells/mm(3) and treatment adherence above 95% are included in the definition of therapeutic success, the rate was elevated (90%) and the factors associated were previous history of adherence to HAART and previous undetectable viral load.

[Usability testing of the canal expander - a new implant for canaloplasty]. / Gebrauchstauglichkeitstest des Kanal-Expander - ein neues Implantat für die Kanaloplastik.

BACKGROUND: Canaloplasty is a bleb-independent glaucoma surgery in which Schlemm's canal is dilated with a microcatheter and viscoelastic material, and stretched by a tensioning suture. The suture stent has numerous drawbacks such as the technical challenging implantation, deficient knowledge of proper suture tension, late loosening of the suture, or suture extrusion into the anterior chamber. The Stegmann Canal Expander (SCE) was developed to replace the suture stent and to make canaloplasty easier and more reproducible. The aim of this test was evaluate the usability regarding effectiveness, efficacy, and satisfaction of the implanting ophthalmologist (test person). METHODS: In an experimental setting, the test persons were asked to implant the SCE in human autopsy eyes with a surgically prepared Schlemm's canal by means of surgical instruments and an operating microscope. The standardised test was performed in terms of participant observation with a subsequent opinion survey based on checklist and photographic documentation. Data for a successful handling of the task and qualitative data from the experience of the test person with the product were anonymised, collected and registered in an assessment sheet. The evaluation comprised the aspects of instructions for use, packaging, identification, handling, and implantation of the SCE. RESULTS: The implantation took 2 to 5 min (mean: 3 min). All questions in the assessment sheet regarding effectiveness, efficacy, and satisfaction (n=35) were answered by all test persons (6/6) with the best category ("completely true"; or "no, no problem"). CONCLUSIONS: The usability of the SCE under standardised and experimental conditions regarding effectiveness, efficacy, and satisfaction has been rated as very positive, especially allowing for the fact that some of the ophthalmologists did not have experience in glaucoma surgery or only little experience in ophthalmic surgery.

Superiority of manual disinfection using pre-soaked wipes over automatic UV-C radiation without prior cleaning.

BACKGROUND: The efficacy of ultraviolet C (UV-C) radiation against a broad spectrum of micro-organisms has been demonstrated in several studies, but differences in the specific doses and the extent of microbial reduction were found. Furthermore, the conditions of laboratory tests differ greatly from reality, such that efficacy achieved in tests may not necessarily be assumed in reality. Consequently, it is important to investigate the effectiveness of UV-C in representative field trials. The aim was therefore to develop and establish a field test to evaluate automatic UV-C in comparison to manual disinfection. METHODS: Before and after disinfection, samples were repeatedly collected from naturally highly contaminated surfaces using the swab technique to obtain representative data sets for disinfected and non-disinfected surfaces. Subsequently, the log reduction values (LRV) and the disinfection success were evaluated for UV-C radiation and full compliant manual disinfection using alcohol-based wipes. RESULTS: Surfaces that are naturally contaminated with bacteria on a regular and nearly uniform basis have been identified as particularly suitable for field testing. Mean contamination was reduced from 23.3 to 1.98 cfu/cm2 (LRV 0.9) and 29.7 to 0.26 cfu/cm2 (LRV 1.2) for UV-C and manual disinfection, respectively. UV-C disinfection achieved 75.5% successful disinfected surfaces, whereas manual disinfection showed 98.1%. CONCLUSIONS: Full compliant manual disinfection showed slightly higher LRVs and disinfection success than automatic UV-C disinfection. Successful, operator-independent UV-C disinfection still has the potential to improve disinfection performance in addition to manual disinfection.

Tolerance of clinical vancomycin-resistant Enterococcus faecium isolates against UV-C light from a mobile source.

BACKGROUND: Admission to a room previously occupied by patients carrying environmentally robust pathogens implies an increased risk of acquiring those pathogens. Therefore, 'No-touch' automated room disinfection systems, including devices based on UV-C irradiation, are discussed to improve terminal cleaning. It is still unclear if clinical isolates of relevant pathogens behave differently under UV-C irradiation compared to laboratory strains used in the approval process of disinfection procedures. In this study we analysed the susceptibility of well characterized clonally divergent vancomycin-resistant enterococci (VRE) strains, including a linezolid-resistant isolate, against UV-C radiation. METHODS: Susceptibility against UV-C of ten clonally divergent clinical isolates of VRE was determined in comparison to the commonly used test organism Enterococcus hirae ATCC 10541. Ceramic tiles contaminated with 105 to 106 colony forming units/25 cm² of the different enterococci were positioned at a distance of 1.0 and 1.5 m and irradiated for 20 s, resulting in a UV-C dose of 50 and 22 mJ/cm², respectively. Reduction factors were calculated after quantitative culture of the bacteria recovered from treated and untreated surfaces. RESULTS: Susceptibility to UV-C varied considerably among the strains studied, with the mean value of the most robust strain being up to a power of ten lower compared to the most sensitive strain at both UV-C doses. The two most tolerant strains belonged to MLST sequence types ST80 and ST1283. The susceptibility of the laboratory strain E. hirae ATCC 10541 ranged between the most sensitive and most tolerant isolates for both irradiation doses. However, for UV-C dose of 22 mJ/cm², the reduction of the most tolerant isolate of ST1283 was statistically significantly lower compared to E. hirae ATCC 10541. The most susceptible strains belonged to the MLST sequence types ST117 and ST203. CONCLUSIONS: These results indicate that UV-C doses reported in the literature are sufficient for the reduction of commonly used reference strains of enterococci but could be insufficient for the reduction of tolerant patient VRE-isolates in a hospital setting. Therefore, for future studies, the most tolerant clinical isolates should be used to validate automated UV-C devices or longer exposure times should be expected to ensure efficacy in the real world.

[Painful and rapidly growing exophytic lesion of the vestibular upper lip]. / Schmerzhafte und rapid exophytisch wachsende Raumforderung der vestibulären Oberlippe.

A 49-year-old healthy woman presented with a painful exophytic-growing mucous lesion on her upper lip that had been primarily noted for 2 weeks. The biopsy showed histological changes of a dense infiltration of lymphoid cell elements. The immunohistological examination presented the diagnosis of primary cutaneous CD30-positive large cell T-cell lymphoma. In the diagnosis of oral lesions cutaneous CD30-positive large cell T-cell lymphoma constitutes a rare but important differential diagnosis.

Extracellular calcium-binding proteins.

Point mutations in Ca2+-binding sites of extracellular matrix proteins have been identified as the cause of human disorders such as Marfansyndrome and pseudoachondroplasia. Although the modes of Ca2+ binding and the effects of point mutations are not yet understood in these two cases, new insight was recently gained by X-ray and NMR structure determinations of several other extracellular proteins; these studies revealed a diversity of functions of Ca2+ ions. Ca2+ may induce a profound conformational change within a single domain, may bridge adjacent domains and thus direct the relative domain orientation and supramolecular structure, or may be involved in carbohydrate and membrane binding.

Antigen-specific helper T cells required for dominant production of an idiotype (THId) are not under immune response (Ir) gene control.

Responder and nonresponder mice primed with poly-(L-glutamic acid,L-lysine,L-phenylalanine) (GLPhe), the response to which is under the control of immune response (Ir) genes, were used as a source of both types of helper T cells required for a T15 idiotype dominated T-dependent anti-phosphorylcholine (PC) response. It was found that the activity of one of the helper T cells needed for an anti-PC response was under major histocompatibility complex (MHC)-linked Ir gene control, and only GLPhe-primed responder mice could be used as a source of these cells. These T cells (ThMHC) whose presence is required for in vivo T-B collaboration are found in normal and anti-mu-treated mice, and their activity depends on the hapten being physically linked to the carrier molecule. By contrast, the activity of the second helper T cell (ThId) required for a T15-dominated anti-PC response was present in both GLPhe-primed responder and nonresponder mice. The ThId cell set that is missing or deficient in anti-mu treated mice can be restored by the addition of T cells from normal, carrier-primed donors and restimulating with the priming carrier. When T cells from GLPhe-primed donors are used as a source of ThId cells, both responder and nonresponder donors provide helper cells capable of inducing syngeneic B cells to produce a T15 dominated anti-Pc response. These results are interpreted to suggest that idiotype recognizing helper T cells (ThId) recognize antigen independent of known Ir gene products.

The expression of anti-poly(LGlu60, LPhe40) idiotypic determinants dictated by the gene products in the major histocompatibility complex.

Antibodies raised in SWR/J mice (H-2q, Igc) to the random copolymer poly(LGlu60, LPhe40) (GPhe) were purified by immunoadsorbent chromatography and used to immunize a New Zealand red rabbit. The rabbit anti-idiotypic antiserum thus produced strongly inhibited the binding of 125I-GPhe by anti-GPhe antisera produced only in mice of H-2q haplotype, and had no effect on the binding of GPhe by anti-GPhe antisera produced in mice of other haplotypes, namely, H-2k and H-2p. The anti-idiotypic antiserum also inhibited the binding of GPhe by anti-GPhe-methylated bovine serum albumin antisera produced only in mice of H-2q haplotype. No linkage to Ig allotype was observed. The anti-GPhe antisera produced in F1 mice the anti-idiotypic antiserum demonstrating the dominant presence in these F1 mice of idiotypic determinants whose expression is dictated by the H-2q major histocompatibility complex (MHC). The anti-idiotypic antiserum also inhibited the binding of 125I-poly)LGlu56, LLys35, LPhe9) and 125I-GPhe antisera produced only in mice of H-2q haplotype. These specificities were also confirmed by the inhibition of the plaque-forming cells. It was concluded that the antibodies produced in mice of H-2q haplotype against GPhe and GLPhe share common idiotypic determinants that are recognized by the anti-idiotypic antiserum. A possible explanation for the unique findings that the expression of anti-GPhe idiotypic determinants in mice of H-2q haplotype are dictated by the gene product in the MHC is that the macrophages in mice of H-2q haplotype present unique determinants of GPhe polymer in the response process to GHphe.

Specific immune response genes of the guinea pig. V. Influence of the GA and GT immune response genes on the specificity of cellular and humoral immune responses to a terpolymer of L-glutamic acid, L-alanine, and L-tyrosine.

The ability of guinea pigs to make immune responses to the random linear copolymer of L-glutamic acid and L-alanine, GA, and to L-glutamic acid and L-tyrosine, GT, is each controlled by a different immune response gene. On the other hand, the random linear terpolymer of L-glutamic acid, L-alanine, and L-tyrosine, GAT, which contains both GA and GT antigenic determinants, is immunogenic in all guinea pigs. After GAT immunization, all animals develop delayed hvpersensitivity and serum antibody specific for GAT. However, only those guinea pigs possessing the GA immune response gene demonstrate cross-reactive delayed hypersensitivity when challenged with GA. In addition, the anti-GAT antisera produced by those animals having the GA gene contain cross-reacting anti-GA antibodies. The sera from guinea pigs lacking the GA gene have no anti-GA antibody activity. Thus, we have demonstrated that a specific immune response gene controlling responsiveness to a "simple" antigen can determine the specificity of both cellular and humoral immune responses to a more complex antigen.

Inclusion group systems and cis-trans effects in responses controlled by the two complementing Ir-GLphi genes.

The immune responses to the random linear terpolymers of L-amino acids, poly-(glu57, lys38, tyr5), poly-(glu51, lys34, tyr15,), and poly-(glu53, lys36, phe11) are each controlled by two dominant H-linked Ir genes. The immune responses to these three related terpolymers demonstrate different H-2 distributions, however, the H-2 patterns are part of a single inclusion group system. The alpha- and beta-genes are dominant; however, most effective gene interactions occur when the two genes are in the cis configuration. The potential significance of this cis-trans effect is discussed.

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.

Role of the major histocompatibility gene products in regulating the antibody response to dinitrophenylated poly(L-Glu55,L-Ala35,L-Phe9)n.

These studies were carried out to investigate the potential helper T cell repertoire specific for the random copolymer poly(L-Glu55,L-Ala35, L-Phe9)n(GL phi 9) of responder, nonresponder, and (responder x nonresponder)F1 murine strains. We tested the ability of these T cells to collaborate with dinitrophenyl (DNP)-specific primary and secondary B lymphocytes of each strain in response to the antigen CNP-GL phi 9 in the splenic-fragment culture system. The results of these experiments show that there are GL phi 9-specific T lymphocytes in the responder, nonresponder, and F1 strains; but that these three GL phi 9-specific T cell populations differ in their collaborative potential. Responder T cells are able to collaborate with their own syngeneic responder B cells as well as the allogeneic nonresponder B cells in a syngeneic fashion. The F1 T cell population resembles that of the nonresponder in its ability to collaborate with only responder B cells in a syngeneic fashion. Analysis carried out using appropriately selected mouse strains indicate that these results are unlikely to be a result of positive or negative allogeneic effects. The results obtained suggest that individuals within a given murine strain do possess the capacity to collaborate in a syngeneic fashion with B cells of any other MHC-allogeneic strain as well as their own MHC-identical B cells. The nonresponder status in the response to GL phi 9 appears to be the result of a deletion of T cells capable of recognizing antigen in the context of B cells of the nonresponder haplotype. Thus, the MHC gene products appear to play a determinative role in shaping the expressed helper T cell specificity repertoire within an individual mouse strain.

The specificity of cellular immune responses II. The structure of antigenic determinants leading to T-lymphocyte stimulation.

T cells from guinea pigs immunized with the hapten 2,4-dinitrophenyl (DNP)-coupled directly to mycobacteria are of interest since they recognize and respond to DNP conjugated to many but not all carriers. The experiments reported here further analyze the structure of the complex, chemically defined antigenic determinants recognized by such T cells. These antigenic determinants can have DNP coupled either to the xi-amino group of lysyl residues or to the hydroxyl group of tyrosyl residues. Furthermore, essential contributions to the determinant recognized by such T cells are made by amino acid residues to which the hapten is not attached. Such residues are thought to be close to the hapten group itself, since introducing a small spacer between hapten and carrier prevents recognition. The hapten itself is also recognized and discriminated from other haptens with great precision by these T lymphocytes. The strain of guinea pig immunized affects the precise specificity characteristics of the responding T cells, in a way that may reflect the activity of histocompatibility-linked immune response genes. Finally, the characteristics of the immunogen have been studied. It is thought that the lipid content of the mycobacteria may be critical in inducing the hapten-reactive T cells, and this is supported by finding similar responses in T cells from guinea pigs immunized with DNP protein to which lipid has been covalently attached. Thus, the T-cell population being studied, while recognizing haptens with great precision, appears to require a larger determinant for activation than do hapten-specific B lymphocytes.

Cell interactions between histoincompatible T and B lymphocytes. IV. Involvement of the immune response (Ir) gene in the control of lymphocyte interactions in responses controlled by the gene.

In the present study we have asked the question of whether F(1) carrier-primed T cells can serve as helper cells for either or both parental B cells when (a) the carrier molecule employed is under genetic control such that one parental strain is a responder and the other is a nonresponder, and (b) the determinant specificity of the parental B cells being assessed is not under genetic control and bears no relationship to the specificity of the carrier molecule. Utilizing the system of immune response gene control of responses to the terpolymer L-glutamic acid-L-lysine-L-tyrosine (GLT) to which A strain mice (H-2(a)) are nonresponders, whereas BALB/c (H-2(d)) and (BALB/c x A)F(1) hybrids (CAF(1)) are responders, these studies demonstrate that GLT-primed T cells of CAF(1) donors can provide for responder BALB/c, but not for nonresponder A/J, the required stimulus for the anti-DNP responses of DNP-specific B cells of these respective parental strains to the DNP conjugate of GLT. The implications of these findings for Ir gene function in physiologic T-B cell interactions are discussed in detail.

The immune response of allophenic mice to the synthetic polymer L-glutamic acid, L-lysine, L-phenylalanine. II. Lack of gene complementation in two nonresponder strains.

The genetic control of the immune response of inbred strains of mice to certain antigens has been demonstrated to be governed by a set of Ir genes linked to the major histocompatibility complex (H-2) of mice (1,2). Until recently, the control was thought to be governed by single, dominant genes, located within the I region of the H-2 complex. Merryman et al. (3) originally demonstrated that the immune response to the synthetic terpolymer L-glutamic acid, L-lysine, L-phenylaline (GLphi) is under dominant, H-2-linked Ir gene control (4-7). This was shown both by crossing two nonresponder parental strains to produce responder offspring in the F(1) generation, and by the analysis of appropriate recombinant stains of mice. The two complementing genes have been mapped in the IA and IC regions of the H-2 complex, and have been termed beta and alpha, respectively (5,6). Thus, any strain of mouse may contain neither, one, or both genes. Only mice containing both genes are capable of responding to GLphi. It has been shown using F(1) hybrid and recombinant strains of mice, that the alpha- and beta-genes can complement each other in either the cis (on the same chromosome) or in the trans (on different chromosomes) position (8). In this paper we report the results of studies aimed at answering the question of whether or not the alpha- and beta- genes can complement each other when they are present in different lymphoid cells. To this end we have constructed allophenic mice composed of two nonresponder strains (A and C57BL/6), which show gene complementation in the F(1) generation. Allophenic mice are chimeras containing two cell types coexisting in a "normal" environment. The mice were tested for the specific cellular composition of the two parental cell types and were found to possess a complete range in the relative proportion of the two cell types. This report demonstrates that regardless of the mixture of cell types present in the allophenic mice, none of them were responders to GLphi. Thus no complementation of the alpha- and beta-genes is seen when the two genes are present in different cells.