Immune cell kinetics and antibody response in COVID-19 patients with low-count monoclonal B-cell lymphocytosis

Low-count monoclonal B-cell lymphocytosis (MBLlo ) has been associated with an underlying immunodeficiency and has recently emerged as a new risk factor for severe COVID-19. Here, we investigated the kinetics of immune cell and antibody responses in blood during COVID-19 of MBLlo versus non-MBL patients. For this study, we analyzed the kinetics of immune cells in blood of 336 COVID-19 patients (74 MBLlo and 262 non-MBL), who had not been vaccinated against SARS-CoV-2, over a period of 43 weeks since the onset of infection, using high-sensitivity flow cytometry. Plasma levels of anti-SARS-CoV-2 antibodies were measured in parallel by ELISA. Overall, early after the onset of symptoms, MBLlo COVID-19 patients showed increased neutrophil, monocyte, and particularly, plasma cell (PC) counts, whereas eosinophil, dendritic cell, basophil, and lymphocyte counts were markedly decreased in blood of a variable percentage of samples, and with a tendency toward normal levels from week +5 of infection onward. Compared with non-MBL patients, MBLlo COVID-19 patients presented higher neutrophil counts, together with decreased pre-GC B-cell, dendritic cell, and innate-like T-cell counts. Higher PC levels, together with a delayed PC peak and greater plasma levels of anti-SARS-CoV-2-specific antibodies (at week +2 to week +4) were also observed in MBLlo patients. In summary, MBLlo COVID-19 patients share immune profiles previously described for patients with severe SARS-CoV-2 infection, associated with a delayed but more pronounced PC and antibody humoral response once compared with non-MBL patients.

Effect of Cry Toxins on Xylotrechus arvicola (Coleoptera: Cerambycidae) Larvae

Simple Summary

Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.

Abstract

The beetle Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly; the latter through the proliferation of wood fungi, which can invade the inside of the plant, decreasing the quality and quantity of its production. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins (Cry1B, Cry1I, Cry3A, Cry7A, and Cry23/37) was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. Cry7Ab and Cry1Ba were the most effective in controlling X. arvicola larvae due to the significant reduction in larvae survival (32.9 and 25.9 days, respectively), and by causing serious alterations in the larvae during the remaining months of their development. The developmental stage of the prepupal and pupal stages was not affected by the previous ingestion of Cry proteins. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, applying them only at the moment when the larvae hatch from the egg outside the grapevine wood (this would only be useful and justified if the economic threshold is exceeded) in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.

Inhibitory activity of Beauveria bassiana and Trichoderma spp. on the insect pests Xylotrechus arvicola (Coleoptera: Cerambycidae) and Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae)

Xylotrechus arvicola is an important pest in vineyards (Vitis vinifera) in the main Iberian wine-producing regions, and Acanthoscelides obtectus causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions with a spray tower, the susceptibility of the immature stages of X. arvicola and A. obtectus against the entomopathogenic fungi Beauveria bassiana and four strains of Trichoderma spp. was evaluated. Both insect pests T. harzianum and B. bassiana showed a good inhibitory activity, accumulating an inhibition on the eggs of values above 85 and 82%, respectively. T. atroviride and T. citrinoviride had a lower inhibitory activity, with inhibition values of 74.1 and 73.3% respectively. These fungi can be considered a highly effective tool for the control during the immature stages of these species.

Reproductive Patterns of Xylotrechus arvicola (Coleoptera: Cerambycidae), an Emerging Pest of Grape-Vines, under Laboratory Conditions

Xylotrechus arvicola (Olivier) is an emerging pest in vineyards ( Vitis vinifera ) in the Iberian Peninsula. Its reproductive biology has been studied in the laboratory in order to develop pest-control measures. Obtained results show that the oviposition period is significantly longer in wild females (16.6 ± 2.9 d) than in laboratory females (9.7 ± 1.3 d), but there are no significant differences in the egg-hatching periods between the wild and the laboratory females. Fecundity is significantly higher in laboratory females (93.9 ± 12.1 eggs per female) than in wild females (56.8 ± 9.2 eggs per female). On the other hand, viability (percentage of viable eggs per female) is significantly higher in wild females (53.7 ± 6.6%) than in laboratory females (22.9 ± 3.6%). Wild females lay fewer eggs over a longer period, while laboratory females concentrate on laying in the first 6 d. X. arvicola females (wild and laboratory) lay the highest number of eggs on the sixth day. The fecundity and viability of eggs are extended over a longer period in wild females than in laboratory females. So X. arvicola is a species in which larvae feed directly affects reproductive patterns. These results suggest that, when larvae feed directly from the natural host, the fecundity period and the viability of eggs increase. So the selection of a host plant could be influenced by the composition of the wood. This behavior of the species can also help to advance knowledge of the biology and ecology of this pest, to be applied in integrated control.