Recent advancements in Weakly Supervised Semantic Segmentation (WSSS) have highlighted the use of image-level Class labels as a form of supervision. Many methods use pseudo-labels from Class Activation Maps (CAMs) to address the limited spatial information in Class labels. However, CAMs generated from Convolutional Neural Networks (CNNs) are often led to focus on prominent features, making it difficult to distinguish foreground objects from their backgrounds. While recent studies show that features from Vision Transformers (ViTs) are more effective in capturing the scene layout than CNNs, the use of hierarchical ViTs has not been widely studied in WSSS. This work introduces "SWTformer" and explores the effect of Swin Transformer’s local-to-global view on improving the accuracy of initial seed CAMs. SWTformer-V1 produces CAMs solely based on patch tokens as its input features. SWTformer-V2 enhances this process by integrating a multi-scale feature fusion mechanism and employing a background-aware mechanism that refines the accuracy of localization Maps, resulting in better differentiation between objects. Experiments on the Pascal VOC 2012 dataset demonstrate that compared to state-of-the-art models, SWTformer-V1 achieves 0.98% Map higher in localization accuracy and generates initial localization Maps that are 0.82% mIoU higher in accuracy while relying solely on the Classification network. SWTformer-V2 enhances the accuracy of the seed CAMs by 5.32% mIoU. Code available at: ttps://github.com/RozhanAhmadi/SWTformer

Background: Natural Killer cells express killer inhibitory receptors specific for HLA-Class I molecules. These receptors could induce signals that determine NK cells ability to mediate cytotoxicity. Purified soluble form of HLA Class I molecules (sHLA) could bind to NK cell receptors and down-regulate the NK killer function.Objective: To evaluate the influence of sHLA and two monoclonal antibodies (mAbs) against killer inhibitory receptors on the poly I:C-treated freshly and IL-2 activated NK cells (LAK cells).Methods: Isolation of CD56+ NK cells and CD56- cells was performed using the magnetic cell separation technique. CD56+ cells were activated by r1L-2 and anti-HLA-B7 specific cytotoxic T lymphocytes (CTLs) were established from C056- cells. Flow cytometry analysis was performed to determine the percentage of CD3, CD16/CD56 and CD8 positive cells. LAK and specific CTLs were tested for cytotoxicity against M4 cells using the 51Cr-release assay. Freshly isolated NK cells and LAK cells were pre-incubated with 0.7-11 µg/ml of sHLA-B7 fused to the Fc portion of IgG molecule and subsequently tested for killing activity. The influence of the sHLA molecule on the cytotoxicity of the cells after treatment with poly I:C as an inducer ofinterferon was also studied. LAK cells were pre-treated with 0.01 to 10µg/ml of two mAbs against NK inhibitory receptors, NKB1 and NKAT2. The effect of these mAbs on the killing activity of poly I:C and non-poly I:C treated LAK cells against K562 target cell was determined.Results: In flow cytometry analysis of LAK cells, 99.5% were found to be CD56+. Analysis of generated CTLs showed 88.4 % positivity for CD8. Cytotoxicity of M4 stimulated CTLs was 12.3% at 1.5/1 E/T ratio to 97.1 % at 25/1 E/T ratio- NK cells had no effect on M4 cells. Anti-NKB1 and Anti-NKAT2 mAbs decreased the cytotoxic activity of LAK cells. These mAbs showed no effect on the poly I:C activated LAK cells. Increasing concentrations of sHLA molecule decreased cytotoxic activity of LAK cells from 17.2% to 13.8% and poly I:C activated NK cells from 62.5% to 51.8%. Treatment of LAK cells with poly I:C and exposure of these cells with increasing concentrations of sHLA resulted in an increase in the target cell killing of LAK cells from 20.1 % to 27.6%.Conclusion: LAK cells were not able to kill M4 cells with high expression of HLA molecules, whereas CTLs were efficient in killing these cells. Recombinant sHLA fusion protein inhibited NK/LAK activity against K562 cells, whereas poly I:C Activation of LAK cells reverted this effect indicating that poly I:C treatment of LAK cells could change the expression of NK inhibitory receptors.