Roadmap on digital holography [Invited]

This Roadmap article on digital holography provides an overview of a vast array of research activities in the field of digital holography. The paper consists of a series of 25 sections from the prominent experts in digital holography presenting various aspects of the field on sensing, 3D imaging and displays, virtual and augmented reality, microscopy, cell identification, tomography, label-free live cell imaging, and other applications. Each section represents the vision of its author to describe the significant progress, potential impact, important developments, and challenging issues in the field of digital holography.

Versatile method for achieving 1% speckle contrast in large-venue laser projection displays using a stationary multimode optical fiber

We propose a method based on quantitative theoretical analysis for achieving speckle contrast of 1% or less in images created by a full-frame laser projection display system. The method employs a stationary multimode optical fiber to achieve the effect of using a rapidly moving diffuser, but without moving the fiber or any other system component. When a suitably large projector lens is used, low-speckle illumination light delivered through the fiber acts in conjunction with wavelength diversity at the projection screen to achieve speckle contrast of 1% in viewed images. We describe in detail how the proposed method might be used with most types of high-power visible lasers being considered for large-venue displays. When used with visible laser diodes, the method may also be suitable for use in laser-based television.

Very efficient speckle contrast reduction realized by moving diffuser device

Speckle noise reduction is best tested on a precise speckle contrast measurement bench, which should be able to measure 100% contrast in fully developed speckle as well as the smallest contrast (for example, less than 10%) after its reduction. On such a test bench, we have measured very efficient speckle contrast reduction by temporal averaging using a moving diffuser on a tuning fork, which vibrates at 100 Hz over 60 microm in amplitude, a distance that is three times the surface roughness correlation length of the diffuser.

Cytotype regulation of P transposable elements in Drosophila melanogaster: repressor polypeptides or piRNAs?

The telomeric P elements TP5 and TP6 are associated with the P cytotype, a maternally inherited condition that represses P-element-induced hybrid dysgenesis in the Drosophila germ line. To see if cytotype repression by TP5 and TP6 might be mediated by the polypeptides they could encode, hobo transgenes carrying these elements were tested for expression of mRNA in the female germ line and for repression of hybrid dysgenesis. The TP5 and TP6 transgenes expressed more germ-line mRNA than the native telomeric P elements, but they were decidedly inferior to the native elements in their ability to repress hybrid dysgenesis. These paradoxical results are inconsistent with the repressor polypeptide model of cytotype. An alternative model based on the destruction of P transposase mRNA by Piwi-interacting (pi) RNAs was supported by finding reduced P mRNA levels in flies that carried the native telomeric P elements, which are inserted in a known major piRNA locus.

Speckle with a finite number of steps

The statistical properties of classical, fully developed speckle must be modified when the speckle is generated by a random walk with a finite number of steps. It is shown that for such speckle, the standard negative-exponential probability density function for speckle intensity often overestimates the probability that the intensity exceeds a given threshold. In addition, while any linear transformation of the fields in a classical speckle pattern does not change the intensity statistics, the same is not true for finite-step speckle. The implications of these facts in certain applications are discussed.

Cytotype regulation by telomeric P elements in Drosophila melanogaster: interactions with P elements from M' strains

P strains of Drosophila are distinguished from M strains by having P elements in their genomes and also by having the P cytotype, a maternally inherited condition that strongly represses P-element-induced hybrid dysgenesis. The P cytotype is associated with P elements inserted near the left telomere of the X chromosome. Repression by the telomeric P elements TP5 and TP6 is significantly enhanced when these elements are crossed into M' strains, which, like P strains, carry P elements, but have little or no ability to repress dysgenesis. The telomeric and M' P elements must coexist in females for this enhanced repression ability to develop. However, once established, it is transmitted maternally to the immediate offspring independently of the telomeric P elements themselves. Females that carry a telomeric P element but that do not carry M' P elements may also transmit an ability to repress dysgenesis to their offspring independently of the telomeric P element. Cytotype regulation therefore involves a maternally transmissible product of telomeric P elements that can interact synergistically with products from paternally inherited M' P elements. This synergism between TP and M' P elements also appears to persist for at least one generation after the TP has been removed from the genotype.

Cytotype regulation by telomeric P elements in Drosophila melanogaster: evidence for involvement of an RNA interference gene

P elements inserted at the left telomere of the X chromosome evoke the P cytotype, a maternally inherited condition that regulates the P-element family in the Drosophila germline. This regulation is completely disrupted in stocks heterozygous for mutations in aubergine, a gene whose protein product is involved in RNA interference. However, cytotype is not disrupted in stocks heterozygous for mutations in two other RNAi genes, piwi and homeless (spindle-E), or in a stock heterozygous for a mutation in the chromatin protein gene Enhancer of zeste. aubergine mutations exert their effects in the female germline, where the P cytotype is normally established and through which it is maintained. These effects are transmitted maternally to offspring of both sexes independently of the mutations themselves. Lines derived from mutant aubergine stocks reestablish the P cytotype quickly, unlike lines derived from stocks heterozygous for a mutation in Suppressor of variegation 205, the gene that encodes the telomere-capping protein HP1. Cytotype regulation by telomeric P elements may be tied to a system that uses RNAi to regulate the activities of telomeric retrotransposons in Drosophila.

Iterative statistical approach to blind image deconvolution

Image deblurring has long been modeled as a deconvolution problem. In the literature, the point-spread function (PSF) is often assumed to be known exactly. However, in practical situations such as image acquisition in cameras, we may have incomplete knowledge of the PSF. This deblurring problem is referred to as blind deconvolution. We employ a statistical point of view of the data and use a modified maximum a posteriori approach to identify the most probable object and blur given the observed image. To facilitate computation we use an iterative method, which is an extension of the traditional expectation-maximization method, instead of direct optimization. We derive separate formulas for the updates of the estimates in each iteration to enhance the deconvolution results, which are based on the specific nature of our a priori knowledge available about the object and the blur.

A mathematical analysis of the DCT coefficient distributions for images

Over the past two decades, there have been various studies on the distributions of the DCT coefficients for images. However, they have concentrated only on fitting the empirical data from some standard pictures with a variety of well-known statistical distributions, and then comparing their goodness of fit. The Laplacian distribution is the dominant choice balancing simplicity of the model and fidelity to the empirical data. Yet, to the best of our knowledge, there has been no mathematical justification as to what gives rise to this distribution. We offer a rigorous mathematical analysis using a doubly stochastic model of the images, which not only provides the theoretical explanations necessary, but also leads to insights about various other observations from the literature. This model also allows us to investigate how certain changes in the image statistics could affect the DCT coefficient distributions.

Discrete cosine transform domain restoration of defocused images

In discrete-cosine-transform-based (DCT-based) compressions such as JPEG it is a common practice to use the same quantization matrix for both encoding and decoding. However, this need not be the case, and the flexibility of designing different matrices for encoding and decoding allows us to perform image restoration in the DCT domain. This is especially useful when we have severe limitations on the computational power, for instance, with in-camera image manipulation for programmable digital cameras. We provide an algorithm that compensates partially for a defocus error in image acquisition, and experimental results show that the restored image is closer to the in-focus image than is the defocused image.

Elements of a hybrid interconnection theory

We present a textbooklike treatment of hybrid systems employing both optical and electrical interconnections. We investigate how these two different interconnection media can be used in conjunction to realize a system not possible with any alone. More specifically, we determine the optimal mix of optical and normally conducting interconnections maximizing a given figure-of-merit function. We find that optical interconnections have relatively little to offer if the optical paths are constrained to lie on a plane (such as in an integrated optics system). However, if optical paths are permitted to leave the plane, they may enable considerable increase in performance. In any event the prize in terms of performance is accompanied by a penalty in terms of system power and/or size.

Design of an optical reconfigurable shared-bus-hypercube interconnect

We propose and evaluate the feasibility of a multiprocessor interconnect based on free-space optics for reducing network latency. The proposed interconnect supports high-throughput network links and can exploit locality of memory references through reconfiguration. Our analysis shows that the proposed interconnect can, in principle, support hundreds of nodes in the static mode and tens of nodes in dynamic mode.

Efficient beam-correcting holographic collimator for laser diodes

We describe a method for recording a beam-correcting holographic collimator for laser diodes in the presence of recording-to-readout wavelength shift. An astigmatism-correcting, beam-shaping hologram recorded with this method at 488 nm displays a high-efficiency, near-diffraction-limited collimation of a diode beam at 820 nm.

Optical oversampled analog-to-digital conversion

A new approach to optical analog-to-digital (A/D) conversion based on oversampling and interpolative coding techniques is described, and both interferometric and noninterferometric architectures based on this method are presented. This new approach combines the high resolution of classical oversampled A/D conversion with the high speed of optical processing technology to extend the resolution and conversion rates beyond that currently possible with other electronic or optical converters. The proposed optical converters are simple, consisting of multiple quantum well self-electro-optic effect devices, photodetectors, and common optical components that are capable of operating at sampling rates of up to 15 Gbits/s and that can provide scalable resolutions of 16 and 8 bits at a conversion rate of 117 and 938 MHz, respectively.

Implications of interconnection theory for optical digital computing

Heat removal, rather than finite interconnect density, is the major mechanism that limits how densely we can pack three-dimensional computing systems of increasing numbers of elements. Thus highly interconnected approaches can be employed without a further increase in system size. The use of optical interconnections for implementing the longer connections of such systems is advantageous. In fact, if the optical communication energy is sufficiently low and large-bit repetition rates are employed, conductors are useful for only the shortest connections and can be dispensed with altogether with little disadvantage. This justifies consideration of an optical digital computer.

Noninterferometric optical subtraction using reflection-electroabsorption modulators

A noninterferometric technique for optical subtraction is demonstrated that employs a multiple-quantum-well reflection-electroabsorption modulator and provides lower insertion loss, larger contrast ratio, and linearity over a larger dynamic range than similar techniques previously reported.

Recursive design of a holographic focusing grating coupler

A method for designing and recording a holographic optical element that is used as a waveguide focusing grating coupler is presented. It is based on recording the holographic coupler with two predistorted wave fronts, derived from interim holograms, whose readout and recording geometries are different. The corrected holographic coupler has almost aberration-free performance even for couplers with very small f/numbers or with large wavelength shift between recording and readout.

Use of synthetic discriminant functions for handwritten-signature verification

Handwritten-signature verification is treated as a two-class synthetic discriminant function (SDF) problem. Images of valid and casually forged signatures are collected and binarized, using an electronic digitizing camera. Performance of this approach with a small number of valid signatures in the training set is examined, and substantial improvement is demonstrated when forgeries are included in the set. In particular, the equal-error rate for the SDF classifier with forgeries included is shown to average approximately 4% across nine different subjects. The effects of image preprocessing on false acceptance and true rejection rates are examined. The use of alternatives to forged signatures in the training matrix is explored. Finally, SDF performance is shown to deteriorate when the tested forgeries are produced with some a priori knowledge of the target signature.

Analytic design of an achromatic double grating coupler

A method for designing a double grating for coupling a polychromatic wave out of a waveguide with negligible angular dispersion is presented. It is based on calculating analytically two different grating functions, such that the chromatic dispersion of the first grating function is compensated by the second grating function. It is shown that the usable wavelength range can be increased by more than 2 orders of magnitude relative to conventional grating couplers for typical angular tolerance.

Design of Fourier-transform holographic lenses in the presence of a recording-readout wavelength shift

A method for recording Fourier-transform holographic lenses, in the presence of a recording-readout wavelength shift, is presented. The method is illustrated with a holographic lens recorded at 488 nm and reconstructed at 633 nm, with high diffraction efficiencies and low aberrations over a wide field of view of +/-10 degrees .

Design of substrate-mode holographic interconnects with different recording and readout wavelengths

A method for recording a substrate-mode holographic interconnect system, composed of two identical holographic optical elements (HOEs) which were recorded on the same plate, has been developed. Since the possible recording wavelengths for efficient holograms are usually different from the readout wavelengths, the holographic elements must be recorded with predistorted wavefronts to assure high diffraction efficiencies and low aberrations. The predistorted wavefronts are derived from simple spherical holograms whose readout geometries differ from those used during recording. The method is illustrated with HOEs recorded at 488 nm and read out at 633 nm. Nearly diffraction-limited imaging and high efficiencies were achieved.

Oblique-incidence liquid-crystal-tunable étalon

The experimental properties and a detailed model of a nematic liquid-crystal-tunable Fabry-Perot étalon with obliquely incident light are reported. As a single-wavelength switch, the étalon has an extinction ratio of 20.3 dB, an insertion loss of -1.7 dB, and a millisecond switching speed. As a filter, the étalon has a finesse of 15.1, a free spectral range of 20.4 nm, and a continuous tuning range of over 40 nm with less than 5 V.

Refractive index modulation mechanism in bleached silver halide holograms

We present a simple technique for observing and studying the onset of microstructure in silver halide gratings, which can also be used to improve processing chemistry.

Ferroelectric liquid-crystal digital scanner

The design and performance of a digital scanner based on ferroelectric liquid-crystal switchable wave plates and passive nematic liquid-crystal prisms are reported. The liquid-crystal prisms function as low-cost, integrable, lowangle birefringent prisms. A 1 x 64 scanner was built with -5.3 dB of average loss. By using an active filter, the limiting mispolarization cross talk of the scanner was reduced from -13 dB to less than -25 dB.

Liquid crystal 1 x N optical switch

The design, experimental results, and analysis of a 1 x N ferroelectric liquid-crystal optical switch based on polarization rotation are reported. The switch is broadband and tolerant to errors in the ferroelectric liquid-crystal tilt angle and cell thickness. Moreover, the cross talk in the switch is noncumulative and independent of the switch size N. The results of an experimental 1 x 4 switch are presented. The switch has a signal-to-cross-talk ratio ranging from 21.6 to 37.1 dB, a switching time of 50 microsec, and a worst-case insertion loss of 3.5 dB.

Liquid crystal optical routing switch

The design and experimental results of a new 2 x 2 optical routing switch based on liquid crystal is reported. The switch uses nematic liquid crystal for polarization beamsplitting and ferroelectric liquid crystal for polarization rotation. The polarization insensitive, broadcast capable, full duplex switch has a signal-to crosstalk ratio of ~20 dB, a switching speed below 250 micros and a measured insertion loss of 1.4 dB. We show that the basic 2 x 2 switch can be extended to form a N x N rearrangeable permutation network.

Optical interconnects: introduction by the feature editors

Some thirteen papers in this 10 Mar. 1990 issue of Applied Optics consider the technology and use of optical interconnects. This introduction also briefly discusses where the field is going.

Optimal wavefront control for adaptive segmented mirrors

A ground-based astronomical telescope with a segmented primary mirror will suffer image-degrading wavefront aberrations from at least two sources: (1) atmospheric turbulence and (2) segment misalignment or figure errors of the mirror itself. This paper describes the derivation of a mirror control feedback matrix that assumes the presence of both types of aberration and is optimum in the sense that it minimizes the meansquared residual wavefront error. Assumptions of the statistical nature of the wavefront measurement errors, atmospheric phase aberrations, and segment misalignment errors are made in the process of derivation. Examples of the degree of correction are presented for three different types of wavefront measurement data and compared to results of simple corrections.

Accuracy requirements of optical linear algebra processors in adaptive optics imaging systems

A ground-based adaptive optics imaging telescope system attempts to improve image quality by measuring and correcting for atmospherically induced wavefront aberrations. The necessary control computations during each cycle will take a finite amount of time, which adds to the residual error variance since the atmosphere continues to change during that time. Thus an optical processor may be well-suited for this task. This paper investigates this possibility by studying the accuracy requirements in a general optical processor that will make it competitive with, or superior to, a conventional digital computer for adaptive optics use.

Optimal maximum correlation filter for arbitrarily constrained devices

Almost all coherent pattern recognition architectures are based on optical correlation of the input with a designed filter. However, the filter can be implemented via many different media, and each medium will impose different realizability constraints on the filter. That is, different media will have different regions of physical realizability. In the past, there has not been much work addressing the problem of designing an optimal filter given an arbitrary region of realizability. This paper presents the theory for just such an optimal filter design. A fast algorithm is presented to implement the theory. The algorithm is demonstrated with two examples.

Arsonate-specific murine T cell clones. V. Antigen presentation by L cells transfected with normal and mutant class II genes

Class II-restricted murine T cell clones specific for the immunogenic determinant L-tyrosine-p-azobenzenearsonate failed to proliferate to Ag presented by L cell lines transfected with and expressing the appropriate class II genes, but are activated to kill the APC in an Ag-dependent, MHC-restricted manner. Inhibition of APC proliferation was used as an assay to determine the relative contributions of polymorphic sites on the class II alpha- and beta-chains to MHC-restricted activation of I-A beta k-restricted cloned T cells. Transfectants expressing A beta k in conjunction with the alpha chain of k, u, or d were equally effective APCs, whereas transfectants expressing A beta u were completely ineffective, implicating the beta-chain as more critical for the presentation of L-tyrosine-p-azobenzenearsonate. Site-directed mutagenesis of polymorphic positions in the beta chain revealed a remarkable stringency for the k haplotype, in contrast to the relaxed alpha-chain requirement. These results, in conjunction with others, indicate that the relative contribution of polymorphic sites on class II alpha- and beta-chains to T cell Ag recognition can differ markedly, and, furthermore, may vary as a function of the Ag.

Arsonate-specific murine T cell clones. V. Antigen presentation by L cells transfected with normal and mutant class II genes

Class II-restricted murine T cell clones specific for the immunogenic determinant L-tyrosine-p-azobenzenearsonate failed to proliferate to Ag presented by L cell lines transfected with and expressing the appropriate class II genes, but are activated to kill the APC in an Ag-dependent, MHC-restricted manner. Inhibition of APC proliferation was used as an assay to determine the relative contributions of polymorphic sites on the class II alpha- and beta-chains to MHC-restricted activation of I-A beta k-restricted cloned T cells. Transfectants expressing A beta k in conjunction with the alpha chain of k, u, or d were equally effective APCs, whereas transfectants expressing A beta u were completely ineffective, implicating the beta-chain as more critical for the presentation of L-tyrosine-p-azobenzenearsonate. Site-directed mutagenesis of polymorphic positions in the beta chain revealed a remarkable stringency for the k haplotype, in contrast to the relaxed alpha-chain requirement. These results, in conjunction with others, indicate that the relative contribution of polymorphic sites on class II alpha- and beta-chains to T cell Ag recognition can differ markedly, and, furthermore, may vary as a function of the Ag.

Immunologic and hematologic consequences in mice of exposure to ozone

Immunologic and hematologic effects of continuous, chronic exposure of mice to ozone are reported. A consistent decrease was found in ability of spleen cells from exposed mice to engage in primary antibody formation. Results from an investigation of the possible presence of suppressor cells were inconclusive Separation of spleen cells into adherent and nonadherent populations revealed suggestive differences between normal and ozone-exposed mice. Among myelopoietic progenitors examined, CFU-S, CFU-GM, CFU-E, CFU-ME, and BFU-E, only the last two named were found to be altered after ozone exposure. The possible bases and implications of these findings are discussed.

The murine T-lymphocyte response to tyrosine-azobenzenearsonate. Characteristics of a low responder haplotype T-cell clone

An I-Ab-restricted, L3T4+ Ly2- T-cell clone, 5R-4F3, specific for ABAtyr was established in culture from a B10.A(5R) mouse. Since b haplotype mice respond weakly to ABAtyr compared to other haplotypes, this is a candidate clone of low responder phenotype. In support of this contention, 5R-4F3 grew very poorly under conditions that supported the vigorous growth of E beta bE alpha k-restricted T-cell clones from the same mouse. The I-A (low responder) and I-E (high responder) restricted T-cell clones also differed in their responses to apc pre-pulsed with antigen, compared to apc with antigen present continuously during culture. The low and high responder clones responded comparably to IL-2. Attempts to elevate the response of C57BL/6 mice to ABAtyr in vivo by injecting them with human recombinant IL-2 and antigen together were only partially successful: C57BL/6 mice treated in this way showed a 3-5-fold increase in their proliferative responses to ABAtyr, which was at best only one quarter of the level of response shown by high responder A/J mice to the same antigen dose.

Optimal binary phase-only matched filters

Many spatial light modulators and computer-generated hologram techniques can very efficiently implement binary phase-only filters. At present, almost all binary phase-only filters are designed by first designing a matched spatial filter and then binarizing it. There is no theoretical basis to expect that such a filter will be optimal. This paper first develops a theory for optimal binary phase-only filters and then presents a numerical algorithm which designs the optimal binary phase-only matched filter for a given image. The filter is optimal in the matched filter sense of maximizing SNR at the output origin. Characteristics of the optimal filter compared to conventional binary phase-only filters are discussed.

Production of a fibronectin-associated lymphokine by cloned mouse T cells

Azobenzenearsonate-specific cloned mouse T cells able to transfer delayed hypersensitivity reactions in vivo produced macrophage agglutination factor (MaggF) after stimulation with mitogen or antigen in vitro. Mitogen (Con A) elicited MAggF production directly from T cells. Responses to Ag were Ag-specific, required syngeneic accessory cells in addition to T cells, and were independent of T cell fine specificity for azobenzenearsonate. Mouse MAggF shared a number of biochemical and immunochemical properties with the fibronectins (FN): 1) high Mr similar to that of plasma FN; 2) binding to gelatin, heparin, and polyclonal antibodies and mAb specific for cellular and plasma FN; 3) inhibition of activity in solution by monoclonal anti-human FN directed against plasma FN gelatin-binding domain; and 4) action on peritoneal exudate macrophages mediated through a FN-receptor cross reactive with one on human monocytes. MAggF production required active protein synthesis and was associated with significant increases in gelatin-binding immunoreactive FN (Mr 440 kDa on immunoblotting) in culture supernatants and T cell lysates. Metabolically labeled peptides could be precipitated by anti-FN from culture supernatants of activated T cells. Stimulated cultures contained significantly more cells with immunohistologically demonstrable cytoplasmic FN than unstimulated control cultures. We suggest that T cell FN is a distinct species of cellular FN which may play an important role in mediating delayed hypersensitivity inflammatory reactions in vivo.

Production of a fibronectin-associated lymphokine by cloned mouse T cells

Azobenzenearsonate-specific cloned mouse T cells able to transfer delayed hypersensitivity reactions in vivo produced macrophage agglutination factor (MaggF) after stimulation with mitogen or antigen in vitro. Mitogen (Con A) elicited MAggF production directly from T cells. Responses to Ag were Ag-specific, required syngeneic accessory cells in addition to T cells, and were independent of T cell fine specificity for azobenzenearsonate. Mouse MAggF shared a number of biochemical and immunochemical properties with the fibronectins (FN): 1) high Mr similar to that of plasma FN; 2) binding to gelatin, heparin, and polyclonal antibodies and mAb specific for cellular and plasma FN; 3) inhibition of activity in solution by monoclonal anti-human FN directed against plasma FN gelatin-binding domain; and 4) action on peritoneal exudate macrophages mediated through a FN-receptor cross reactive with one on human monocytes. MAggF production required active protein synthesis and was associated with significant increases in gelatin-binding immunoreactive FN (Mr 440 kDa on immunoblotting) in culture supernatants and T cell lysates. Metabolically labeled peptides could be precipitated by anti-FN from culture supernatants of activated T cells. Stimulated cultures contained significantly more cells with immunohistologically demonstrable cytoplasmic FN than unstimulated control cultures. We suggest that T cell FN is a distinct species of cellular FN which may play an important role in mediating delayed hypersensitivity inflammatory reactions in vivo.

Design considerations for holographic optical interconnects

The geometrical design characteristics of multiple-image holograms are evaluated. A figure of merit expressing these characteristics as a function of the hologram diameter and the distance between the hologram and the image plane is developed. This value is then used to compare two designs which are capable of forming several hundred interconnections. The results indicate that these connections can be formed between points on the substrate separated by 2-3 cm provided that the holograms are separated from the substrate plane by 0.5-1 cm. Each hologram design is experimentally demonstrated in bleached photographic emulsions.

Arsonate-specific murine T cell clones. IV. Properties of I-E- and I-A-restricted clones

The T cell antigen L-tyrosine-p-azobenzenearsonate is unique in being a simple determinant that can be presented in the context of both I-A and I-E. I-E-restricted T cell clones derived from B10.A(5R) mice were found to fall into three groups: Type I clones recognized antigen only in the context of syngeneic apcs, Type II clones recognized antigen with the same highly specific major histocompatibility complex restriction but in addition proliferated in response to allogeneic stimuli; Type III clones were "degenerate" in their major histocompatibility complex-restricted recognition of antigen and proliferated when antigen-presenting cells bearing Eb beta Ek alpha (syngeneic), Ek beta Ek alpha, or Ed beta Ed alpha were used. These observations allow some conclusions to be drawn about sites on the I-E molecule that may be functionally significant in the presentation of this antigen. By using the B cell hybridoma LK35.2 as target cells, some of these T cell clones act as cytotoxic cells in the Class II-restricted manner predicted from the results of proliferative assays. Class II-restricted cytotoxicity can therefore be controlled by both I-A and I-E mouse Ir gene loci.

Arsonate-specific murine T cell clones. IV. Properties of I-E- and I-A-restricted clones

The T cell antigen L-tyrosine-p-azobenzenearsonate is unique in being a simple determinant that can be presented in the context of both I-A and I-E. I-E-restricted T cell clones derived from B10.A(5R) mice were found to fall into three groups: Type I clones recognized antigen only in the context of syngeneic apcs, Type II clones recognized antigen with the same highly specific major histocompatibility complex restriction but in addition proliferated in response to allogeneic stimuli; Type III clones were "degenerate" in their major histocompatibility complex-restricted recognition of antigen and proliferated when antigen-presenting cells bearing Eb beta Ek alpha (syngeneic), Ek beta Ek alpha, or Ed beta Ed alpha were used. These observations allow some conclusions to be drawn about sites on the I-E molecule that may be functionally significant in the presentation of this antigen. By using the B cell hybridoma LK35.2 as target cells, some of these T cell clones act as cytotoxic cells in the Class II-restricted manner predicted from the results of proliferative assays. Class II-restricted cytotoxicity can therefore be controlled by both I-A and I-E mouse Ir gene loci.

Arsonate-specific murine T cell clones. III. Correlation between clonotype expression and fine specificity for analogs of L-tyrosine-p-azobenzenearsonate

Despite recent advances in our understanding of T cell antigen receptor structure, relatively little is known about the role of this receptor in MHC-restricted antigen recognition. To study this problem, we have developed a panel of ABA-Tyr-reactive, I-Ak-restricted T cell clones that differ in their ability to recognize structural analogs of ABA-Tyr. Three fine specificity groups have been defined. In each group, ABA-Tyr elicited the strongest response of any of the antigens tested. Group I clones responded to ABA-conjugated hydroxyphenyl-ethanol (ABA-HPE). Group II clones responded to ABA-conjugated hydroxyphenyl-methanol (ABA-HPM) but not to ABA-HPE, and group III clones responded only to ABA-Tyr. These studies show that differences as small as a single methylene group can dramatically affect fine specificity. Because these clones are all I-Ak-restricted, it was possible to correlate receptor serology with fine specificity. To this end, monoclonal anti-clonotypes were made against clone 16-F2 from group I and used to study the relationship between fine specificity and clonotype expression. A panel of 15 T cell clones studied with four anti-clonotype antibodies showed a strict correlation between clonotype expression and fine specificity. Taken together, these data suggest that the structure recognized by the anti-clonotype antibodies is a determinant of receptor fine specificity.

Arsonate-specific murine T cell clones. III. Correlation between clonotype expression and fine specificity for analogs of L-tyrosine-p-azobenzenearsonate

Despite recent advances in our understanding of T cell antigen receptor structure, relatively little is known about the role of this receptor in MHC-restricted antigen recognition. To study this problem, we have developed a panel of ABA-Tyr-reactive, I-Ak-restricted T cell clones that differ in their ability to recognize structural analogs of ABA-Tyr. Three fine specificity groups have been defined. In each group, ABA-Tyr elicited the strongest response of any of the antigens tested. Group I clones responded to ABA-conjugated hydroxyphenyl-ethanol (ABA-HPE). Group II clones responded to ABA-conjugated hydroxyphenyl-methanol (ABA-HPM) but not to ABA-HPE, and group III clones responded only to ABA-Tyr. These studies show that differences as small as a single methylene group can dramatically affect fine specificity. Because these clones are all I-Ak-restricted, it was possible to correlate receptor serology with fine specificity. To this end, monoclonal anti-clonotypes were made against clone 16-F2 from group I and used to study the relationship between fine specificity and clonotype expression. A panel of 15 T cell clones studied with four anti-clonotype antibodies showed a strict correlation between clonotype expression and fine specificity. Taken together, these data suggest that the structure recognized by the anti-clonotype antibodies is a determinant of receptor fine specificity.