BL-01, an Fc-bearing, tetravalent CD20 × CD5 bispecific antibody, redirects multiple immune cells to kill tumors in vitro and in vivo.

BACKGROUND AIMS: The authors describe here a novel therapeutic strategy combining a bispecific antibody (bsAb) with cytokine-induced killer (CIK) cells. METHODS: The authors have designed, produced and purified a novel tetravalent IgG1-like CD20 × CD5 bsAb called BL-01. The bsAb is composed of a fused heavy chain and two free light chains that pair correctly to the heavy chain sequences thanks to complementary mutations in the monoclonal antibody 2 CH1/CL sequences. RESULTS: The authors show that BL-01 can bind specifically to CD20 and CD5 with an affinity of 4-6 nM, demonstrating correct pairing of two light chains to the fused heavy chain. The CD20 × CD5 BL-01 bsAb has a functional human IgG1 Fc and can induce up to 65% complement-dependent cytotoxicity of a CD20+ lymphoma cell line in the presence of human complement, similar to anti-CD20 rituximab. The bsAb also induces significant natural killer cell activation and antibody-dependent cytotoxicity of up to 25% as well as up to 65% phagocytosis by human macrophages in the presence of CD20+ tumor cells. The BL-01 bsAb binds to CD20 and CD5 simultaneously and can redirect CIK cells in vitro to kill CD20+ targets, increasing the cytotoxicity of CIK cells by about 3-fold. The authors finally show that the CD20 × CD5 BL-01 bsAb synergizes with CIK cells in vivo in controlling tumor growth and prolonging survival of nonobese diabetic/severe combined immunodeficiency mice inoculated with a patient-derived, aggressive diffuse large B-cell lymphoma xenograft. CONCLUSIONS: The authors suggest that the efficacy of bsAb in vivo is due to the combined activation of innate immunity by Fc and redirection of CIK cells to kill the tumor target.

Left Brain Asymmetry of the Planum Temporale in a Nonhominid Primate: Redefining the Origin of Brain Specialization for Language.

The planum temporale (PT) is a critical region of the language functional network in the human brain showing a striking size asymmetry toward the left hemisphere. Historically considered as a structural landmark of the left-brain specialization for language, a similar anatomical bias has been described in great apes but never in monkeys-indicating that this brain landmark might be unique to Hominidae evolution. In the present in vivo magnetic resonance imaging study, we show clearly for the first time in a nonhominid primate species, an Old World monkey, a left size predominance of the PT among 96 olive baboons (Papio anubis), using manual delineation of this region in each individual hemisphere. This asymmetric distribution was quasi-identical to that found originally in humans. Such a finding questions the relationship between PT asymmetry and the emergence of language, indicating that the origin of this cerebral specialization could be much older than previously thought, dating back, not to the Hominidae, but rather to the Catarrhini evolution at the common ancestor of humans, great apes and Old World monkeys, 30-40 million years ago.

The average baboon brain: MRI templates and tissue probability maps from 89 individuals.

The baboon (Papio) brain is a remarkable model for investigating the brain. The current work aimed at creating a population-average baboon (Papio anubis) brain template and its left/right hemisphere symmetric version from a large sample of T1-weighted magnetic resonance images collected from 89 individuals. Averaging the prior probability maps output during the segmentation of each individual also produced the first baboon brain tissue probability maps for gray matter, white matter and cerebrospinal fluid. The templates and the tissue probability maps were created using state-of-the-art, freely available software tools and are being made freely and publicly available: http://www.nitrc.org/projects/haiko89/ or http://lpc.univ-amu.fr/spip.php?article589. It is hoped that these images will aid neuroimaging research of the baboon by, for example, providing a modern, high quality normalization target and accompanying standardized coordinate system as well as probabilistic priors that can be used during tissue segmentation.

Brain correlates of phonological recoding of visual symbols.

Learning to read involves setting up associations between meaningless visual inputs (V) and their phonological representations (P). Here, we recorded the brain signals (ERPs and fMRI) associated with phonological recoding (i.e., V-P conversion processes) in an artificial learning situation in which participants had to learn the associations between 24 unknown visual symbols (Japanese Katakana characters) and 24 arbitrary monosyllabic names. During the learning phase on Day 1, the strength of V-P associations was manipulated by varying the proportion of correct and erroneous associations displayed during a two-alternative forced choice task. Recording event related potentials (ERPs) during the learning phase allowed us to track changes in the processing of these visual symbols as a function of the strength of V-P associations. We found that, at the end of the learning phase, ERPs were linearly affected by the strength of V-P associations in a time-window starting around 200ms post-stimulus onset on right occipital sites and ending around 345ms on left occipital sites. On Day 2, participants had to perform a matching task during an fMRI session and the strength of these V-P associations was again used as a probe for identifying brain regions related to phonological recoding. Crucially, we found that the left fusiform gyrus was gradually affected by the strength of V-P associations suggesting that this region is involved in the brain network supporting phonological recoding processes.

Boosted activation of right inferior frontoparietal network: a basis for illusory movement awareness.

The feeling of illusory movement is considered important in the study of human behavior because it is deeply related to motor consciousness. However, the neural basis underlying the illusion of movement remains to be understood. Following optimal vibratory stimulation of muscle tendon, certain subjects experience illusory movements while others do not. In the present fMRI study, we sought to uncover the neural basis of illusory movement awareness by contrasting a posteriori these two types of subjects. Examining fMRI data using leave-one-subject-out general linear models and region of interest analyses, we found that a non-limb-specific associative network, including the opercular part of the right inferior frontal gyrus and the right inferior parietal lobule, was more active in subjects with illusions. On the other hand, levels of activation in other brain areas involved in kinaesthetic processing were rather similar between the two subsamples of subjects. These results suggest that activation of the right inferior frontoparietal areas, once passed a certain threshold, forms the basis of illusory movements. This is consistent with the global neuronal workspace hypothesis that associates conscious processing with surges of frontoparietal activity.

Functional specificity in the motor system: Evidence from coupled fMRI and kinematic recordings during letter and digit writing.

A few intriguing neuropsychologial studies report dissociations where agraphic patients are severely impaired for writing letters whereas they write digits nearly normally. Here, using functional magnetic resonance imaging (fMRI) together with graphic tablet recordings, we tested the hypothesis that the motor patterns for writing letters are coded in specific regions of the cortex. We found a set of three regions that were more strongly activated when participants wrote letters than when they wrote digits and whose response was not explained by low-level kinematic features of the graphic movements. Two of these regions (left dorsal premotor cortex and supplementary motor complex) are part of a motor control network. The left premotor activation belongs to what is considered in the literature a key area for handwriting. Another significant activation, likely related to phoneme-to-grapheme conversion, was found in the right anterior insula. This constitutes the first neuroimaging evidence of functional specificity derived from experience in the cortical motor system.

Development of a Bispecific IgG1 Antibody Targeting BCMA and PDL1.

We designed, produced, and purified a novel IgG1-like, bispecific antibody (bsAb) directed against B-cell maturation antigen (BCMA), expressed by multiple myeloma (MM) cells, and an immune checkpoint inhibitor (ICI), PDL1, expressed in the MM microenvironment. The BCMA×PDL1 bsAb was fully characterized in vitro. BCMA×PDL1 bound specifically and simultaneously, with nM affinity, to both native membrane-bound antigens and to the recombinant soluble antigen fragments, as shown by immunophenotyping analyses and surface plasmon resonance (SPR), respectively. The binding affinity of bsAb for PDL1 and BCMA was similar to each other, but PDL1 affinity was about 10-fold lower in the bsAb compared to parent mAb, probably due to the steric hindrance associated with the more internal anti-PDL1 Fab. The bsAb was also able to functionally block both antigen targets with IC50 in the nM range. The bsAb Fc was functional, inducing human-complement-dependent cytotoxicity as well as ADCC by NK cells in 24 h killing assays. Finally, BCMA×PDL1 was effective in 7-day killing assays with peripheral blood mononuclear cells as effectors, inducing up to 75% of target MM cell line killing at a physiologically attainable, 6 nM, concentration. These data provide the necessary basis for future optimization and in vivo testing of this novel bsAb.

Broca's cerebral asymmetry reflects gestural communication's lateralisation in monkeys (Papio anubis).

Manual gestures and speech recruit a common neural network, involving Broca's area in the left hemisphere. Such speech-gesture integration gave rise to theories on the critical role of manual gesturing in the origin of language. Within this evolutionary framework, research on gestural communication in our closer primate relatives has received renewed attention for investigating its potential language-like features. Here, using in vivo anatomical MRI in 50 baboons, we found that communicative gesturing is related to Broca homologue's marker in monkeys, namely the ventral portion of the Inferior Arcuate sulcus (IA sulcus). In fact, both direction and degree of gestural communication's handedness - but not handedness for object manipulation are associated and correlated with contralateral depth asymmetry at this exact IA sulcus portion. In other words, baboons that prefer to communicate with their right hand have a deeper left-than-right IA sulcus, than those preferring to communicate with their left hand and vice versa. Interestingly, in contrast to handedness for object manipulation, gestural communication's lateralisation is not associated to the Central sulcus depth asymmetry, suggesting a double dissociation of handedness' types between manipulative action and gestural communication. It is thus not excluded that this specific gestural lateralisation signature within the baboons' frontal cortex might reflect a phylogenetical continuity with language-related Broca lateralisation in humans.

Remission from mania is associated with a decrease in amygdala activation during motor response inhibition.

OBJECTIVES: Neuroimaging studies of bipolar disorder (BD) have provided evidence of brain functional abnormalities during both the states of mania and remission. However, the differences in brain function between these two states are still poorly known. In the current study, we aimed to use a longitudinal design to examine the functional changes associated with symptomatic remission from mania within the brain network underlying motor response inhibition. METHODS: Using event-related functional magnetic resonance imaging (fMRI), 10 BD patients and 10 healthy subjects were imaged twice while performing a Go/NoGo task. Patients were in a manic state when they underwent the first scan and fully remitted during the second scan. A mixed-effect ANOVA was used to identify brain regions showing differences in activation change over time between the two groups. RESULTS: The left amygdala was the only brain region to show a time-dependent change in activation that was significantly different between BD patients and healthy subjects. Further analyses revealed that this difference arose from the patient group, in which amygdala activation was decreased between mania and subsequent remission. CONCLUSIONS: This finding suggests that a decrease in left amygdala responsiveness is a critical phenomenon associated with remission from mania. It emphasizes the relevance of longitudinal approaches for identifying neurofunctional modifications associated with mood changes in BD.

Reduced brain activation in euthymic bipolar patients during response inhibition: an event-related fMRI study.

Deficits in inhibitory control have been reported in euthymic bipolar disorder patients. To date, data on the neuroanatomical correlates of these deficits are exclusively related to cognitive inhibition. This study aimed to examine the neural substrates of motor inhibitory control in euthymic bipolar patients. Groups of 20 patients with euthymic bipolar disorder and 20 demographically matched healthy subjects underwent event-related functional magnetic resonance imaging while performing a Go-NoGo task. Between-group differences in brain activation associated with motor response inhibition were assessed by using random-effects analyses. Although euthymic bipolar patients and healthy subjects performed similarly on the Go-NoGo task, they showed different patterns of brain activation associated with response inhibition. Specifically, patients exhibited significantly decreased activation in the left frontopolar cortex and bilateral dorsal amygdala compared with healthy subjects. There were no brain regions that were significantly more activated in patients than in healthy subjects. The findings suggest that euthymic bipolar patients have deficits in their ability to engage the left frontopolar cortex and bilateral dorsal amygdala during response inhibition. Further research should ascertain the role that such deficits may play in the emergence of impulsive behaviors that characterize bipolar disorder.

Handedness in monkeys reflects hemispheric specialization within the central sulcus. An in vivo MRI study in right- and left-handed olive baboons.

Handedness, one of the most prominent expressions of laterality, has been historically considered unique to human. This noteworthy feature relates to contralateral inter-hemispheric asymmetries in the motor hand area following the mid-portion of the central sulcus. However, within an evolutionary approach, it remains debatable whether hand preferences in nonhuman primates are associated with similar patterns of hemispheric specialization. In the present study conducted in Old world monkeys, we investigate anatomical asymmetries of the central sulcus in a sample of 86 olive baboons (Papio anubis) from in vivo T1 anatomical magnetic resonance images (MRI). Out of this sample, 35 individuals were classified as right-handed and 28 as left-handed according to their hand use responses elicited by a bimanual coordinated tube task. Here we report that the direction and degree of hand preference (left or right), as measured by this manual task, relates to and correlates with contralateral hemispheric sulcus depth asymmetry, within a mid-portion of the central sulcus. This neuroanatomical manifestation of handedness in baboons located in a region, which may correspond to the motor hand area, questions the phylogenetic origins of human handedness that may date back to their common ancestor, 25-40 millions years ago.

Proactive inhibitory control of movement assessed by event-related fMRI.

Many neuronal processes play a role in the overall performance of inhibition tasks, often making it difficult to associate particular behavioral results to specific processes and structures. Indeed, in classical Go/NoGo, Stop or subliminal masked-prime tasks, inhibition is usually triggered at the same time as the sensorimotor processes involved in movement selection and conflict monitoring. To account for motor inhibition, many conflicting candidate structures, which depend on specific task requirements, have been proposed. In the present paper, first we used a simple reaction (RT) time task and, second, we took advantage of the fact that volitional inhibition is usually implemented before any stimulus occurs when subjects are aware that a warning signal will be presented before a target. This proactive inhibition would be intended to prevent anticipated responses and would be lifted as soon as the warning signal has been identified. In other words, we postulate that the same event does not trigger both inhibition and target processing, and that, indeed, these mechanisms can be separated in time. Event-related fMRI revealed that the medial prefrontal cortex and the inferior parietal cortex may be responsible for proactive inhibition, and that the primary motor cortex, the supplementary motor cortex and the putamen are the likely targeted sites of this inhibition. We conclude that executive control in these tasks may consist of switching from controlled inhibition (suppression of the neuronal processes underlying movement initiation) to automatic sensorimotor processing. The possible contribution of the medial prefrontal cortex to the tonic inhibition state adds new perspectives to possible meanings of a "default mode of brain function".

Deciphering human motion to discriminate social interactions: a developmental neuroimaging study.

Non-verbal communication plays a major role in social interaction understanding. Using functional magnetic resonance imaging, we explored the development of the neural networks involved in social interaction recognition based on human motion in children (8-11), adolescents (13-17), and adults (20-41). Participants watched point-light videos depicting two actors interacting or moving independently and were asked whether these agents were interacting or not. All groups successfully performed the discrimination task, but children had a lower performance and longer response times than the older groups. In all three groups, the posterior parts of the superior temporal sulci and middle temporal gyri, the inferior frontal gyri and the anterior temporal lobes showed greater activation when observing social interactions. In addition, adolescents and adults recruited the caudate nucleus and some frontal regions that are part of the mirror system. Adults showed greater activations in parietal and frontal regions (part of them belonging to the social brain) than adolescents.An increased number of regions that are part of the mirror system network or the social brain, as well as the caudate nucleus, were recruited with age. In conclusion, a shared set of brain regions enabling the discrimination of social interactions from neutral movements through human motion is already present in 8-year-old children. Developmental processes such as refinements in the social brain and mirror system would help grasping subtle cues in non-verbal aspects of social interactions.

Testing the physiological plausibility of conflicting psychological models of response inhibition: A forward inference fMRI study.

The neural mechanisms underlying response inhibition and related disorders are unclear and controversial for several reasons. First, it is a major challenge to assess the psychological bases of behaviour, and ultimately brain-behaviour relationships, of a function which is precisely intended to suppress overt measurable behaviours. Second, response inhibition is difficult to disentangle from other parallel processes involved in more general aspects of cognitive control. Consequently, different psychological and anatomo-functional models coexist, which often appear in conflict with each other even though they are not necessarily mutually exclusive. The standard model of response inhibition in go/no-go tasks assumes that inhibitory processes are reactively and selectively triggered by the stimulus that participants must refrain from reacting to. Recent alternative models suggest that action restraint could instead rely on reactive but non-selective mechanisms (all automatic responses are automatically inhibited in uncertain contexts) or on proactive and non-selective mechanisms (a gating function by which reaction to any stimulus is prevented in anticipation of stimulation when the situation is unpredictable). Here, we assessed the physiological plausibility of these different models by testing their respective predictions regarding event-related BOLD modulations (forward inference using fMRI). We set up a single fMRI design which allowed for us to record simultaneously the different possible forms of inhibition while limiting confounds between response inhibition and parallel cognitive processes. We found BOLD dynamics consistent with non-selective models. These results provide new theoretical and methodological lines of inquiry for the study of basic functions involved in behavioural control and related disorders.

Premotor activations in response to visually presented single letters depend on the hand used to write: a study on left-handers.

In a previous fMRI study on right-handers (Rhrs), we reported that part of the left ventral premotor cortex (BA6) was activated when alphabetical characters were passively observed and that the same region was also involved in handwriting [Longcamp, M., Anton, J. L., Roth, M., & Velay, J. L. (2003). Visual presentation of single letters activates a premotor area involved in writing. NeuroImage, 19, 1492-1500]. We therefore suggested that letter-viewing may induce automatic involvement of handwriting movements. In the present study, in order to confirm this hypothesis, we carried out a similar fMRI experiment on a group of left-handed subjects (Lhrs). We reasoned that if the above assumption was correct, visual perception of letters by Lhrs might automatically activate cortical motor areas coding for left-handed writing movements, i.e., areas located in the right hemisphere. The visual stimuli used here were either single letters, single pseudoletters, or a control stimulus. The subjects were asked to watch these stimuli attentively, and no response was required. The results showed that a ventral premotor cortical area (BA6) in the right hemisphere was specifically activated when Lhrs looked at letters and not at pseudoletters. This right area was symmetrically located with respect to the left one activated under the same circumstances in Rhrs. This finding supports the hypothesis that visual perception of written language evokes covert motor processes. In addition, a bilateral area, also located in the premotor cortex (BA6), but more ventrally and medially, was found to be activated in response to both letters and pseudoletters. This premotor region, which was not activated correspondingly in Rhrs, might be involved in the processing of graphic stimuli, whatever their degree of familiarity.

Articulation in early and late bilinguals' two languages: evidence from functional magnetic resonance imaging.

The network of cortical and subcortical regions that contribute to articulation was examined in bilinguals using functional magnetic resonance imaging. Participants were all fluent in French and English: half were bilingual from birth and half were 'late bilinguals' who had learned French after the age of 12. Overt articulation resulted in the bilateral activation of the motor cortex, basal ganglia and cerebellum, and also the supplementary motor area, independent of the language spoken. Furthermore, the threshold and extent of the network involved in articulation was identical for the two bilingual groups with the exception of greater variation in the left putamen for the late bilinguals. These data challenge claims that age of acquisition results in fundamental differences in the neural substrates that subserve language in bilinguals.

Motor and parietal cortical areas both underlie kinaesthesia.

Tendon vibration has long been known to evoke perception of illusory movements through activation of muscle spindle primary endings. Few studies, however, have dealt with the cortical processes resulting in these kinaesthetic illusions. We conceived an fMRI experiment to investigate the cortical structures taking part in these illusory perceptions. Since muscle spindle afferents project onto different cortical areas involved in motor control it was necessary to discriminate between activation related to sensory processes and activation related to perceptual processes. To this end, we designed and compared different conditions. In two illusion conditions, covibration at different frequencies of the tendons of the right wrist flexor and extensor muscle groups evoked perception of slow or fast illusory movements. In a no illusion condition, covibration at the same frequency of the tendons of these antagonist muscle groups did not evoke a sensation of movement. Results showed activation of most cortical areas involved in sensorimotor control in both illusion conditions. However, in most areas, activation tended to be larger when the movement perceived was faster. In the no illusion condition, motor and premotor areas were little or not activated. Specific contrasts showed that perception of an illusory movement was specifically related to activation in the left premotor, sensorimotor, and parietal cortices as well as in bilateral supplementary motor and cingulate motor areas. We conclude that activation in motor as well as in parietal areas is necessary for a kinaesthetic sensation to arise.

An fMRI study of music sight-reading.

The brain areas involved in music reading were investigated using fMRI. In order to evaluate the specificity of these areas we compared reading music notation to reading verbal and number notations in a task that required professional pianists to play the notes (in musical and verbal notations) and the numbers displayed on a 5-key keyboard. Overall, the three tasks revealed a similar pattern of activated brain areas. However, direct contrasts between the music notation and the verbal or the numerical notation tasks also revealed specific major foci of activation in the right occipito-temporal junction, superior parietal lobule and the intraparietal sulcus. We interpret the right occipito-temporal difference as due to differences at the encoding level between notes, words and numbers. This area might be analogous to one described for words, called the visual word form area. The parietal activations are discussed in terms of visuo-motor transcoding pathways that differ for the three types of notations used. Finally, we present a model of music reading that can possibly explain our findings.

Retrospective intra-scan motion correction.

This paper analyzes the effects of intra-scan motion and demonstrates the possibility of correcting them directly in k-space with a new automatic retrospective method. The method is presented for series of 2D acquisitions with Cartesian sampling. Using a reference k-space acquisition (corrected for translations) within the series, intra-scan motion parameters are accurately estimated for each trajectory in k-space of each data set in the series resulting in pseudo-random sample positions. The images are reconstructed with a Bayesian estimator that can handle sparse arbitrary sampling in k-space and reduces intra-scan rotation artefacts to the noise level. The method has been assessed by means of a Monte Carlo study on axial brain images for different signal-to-noise ratios. The accuracy of motion estimates is better than 0.1 degrees for rotation, and 0.1 and 0.05 pixel, respectively, for translation along the read and phase directions for signal-to-noise ratios higher than 6 of the signals on each trajectory. An example of reconstruction from experimental data corrupted by head motion is also given.

Lateral occipitotemporal cortex and action representation.

Representation of body and body movements is essential for identifying others intentions or actions or for learning from them. Over the last 10 years, a large collection of research has demonstrated that body representations are distributed across a widely distributed brain network. In this functional magnetic resonance imaging study, we focus on lateral occipitotemporal cortex (LOTC), a recently identified brain region that could represent the body in a multisensory and dynamic manner. We addressed the question of LOTC involvement in visual processing of others׳ actions through a factorial analysis that manipulated the meaning of an observed action, completed by a psychophysiological interaction analysis. The results show that only left LOTC was significantly activated in relation to others׳ actions meaning. In addition, only left LOTC was activated during both action observation and action production but it was more dorsal than the activation related to the meaning of observed actions. Furthermore, the psychophysiological interaction analysis showed that when watching meaningless actions, the more dorsal part of the LOTC (the area active during both action production and action observation) had higher functional connectivity with primary visual areas while the more ventral part (that responded to action meaning) had higher correlation with anterior cingulate and medioprefrontal cortices. Taken together these results plead in favour of a strong implication of left LOTC in action observation and understanding, with a possible functional specialisation between the more ventral and the more dorsal parts of LOTC.